(FORTUNE Magazine) – You're sitting at your desk, minding your own business, when Sophia Loren approaches you from behind. (If you prefer, substitute Michelle Pfeiffer, Brad Pitt, Gary Cooper--or whoever makes your skin tingle.) Feeling the warm touch of a hand on your shoulder, you notice the divine reflection on your computer screen. Breathless, you swivel around, quickly slipping off your telephone headset and smooshing hair over your bald spot. Sophia looks deep into your eyes, mesmerizing you, depriving you of independent will, reaching into your very soul. Her lips part. "I've just bought a personal computer," she says--"What software should I use to organize my life?"

What would you tell her, once your heart started beating again? I've been pondering this question for months now, fiddling with a dozen programs of the type called personal information managers, or PIMs. Early on, I found myself comparing these programs to movies, as a way of defining their very distinct personalities. The digital equivalent of a Filofax, PIM software typically combines the functions of an address book, appointment book, alarm clock, to-do list, phone dialer, and note pad, and sometimes includes doodads such as a calculator, an expense tracker, or a filer of Internet messages. Most PIMs are essentially databases that store information in structured ways. The more a program links all your pieces of data together-phone numbers and appointments and company names--the more powerful, and complicated, it will be.

As a guy who routinely places 30 to 50 calls per day, I love zapping from my word-processing program to a PIM with a single mouse-click, locating a phone number with a couple more clicks, and then dialing by clicking on an icon. If I reach the person I'm seeking, some PIMs can log the call automatically, while I zap back to word processing to take notes. Or if I leave a message, simply clicking on a check box can create a detailed entry in a callback file. For personal business, some PIMs let me switch to my calling card just by invoking a menu, making it easy to keep track of expenses for multiple accounts.

No software touches your life more intimately than a PIM. Unless delicately attuned to your temperament, it will only chafe and annoy you. (That's why people networked together at the office, forced to use whatever programs Herr Direktor chooses, often complain.) Picking the PIM that's right for you requires a balanced understanding of the programs' personalities and your needs. It's like deciding what movie to watch, except that the decision can haunt you forever--imagine being forced to watch Judge Dredd or even Pocahontas every time you fire up your PC. So ask yourself: Are you rigid or flexible? What's more important to you, scheduling or keeping track of contacts? Are you the type who pores over instruction manuals, or do you expect software to work perfectly right out of the box? Must your PIM be industrial strength, or will a lite product suffice?

And when your computer is on, how do you spend your time? Salespeople might prefer Symantec's ACT!, a program for users primarily interested in tracking their business prospects. Someone who usually works with a word processor, even while making calls and booking appointments, will prefer a PIM that integrates its functions with those of popular programs such as WordPerfect and Microsoft Word. Ecco Pro from NetManage is a strong contender in that category. For a stripped-down PIM focused on address retrieval, consider Baseline Data Systems' Info Accelerator.

I TESTED only PIMs that work with Microsoft Windows, since that's what office PCs overwhelmingly use. Not many programs have yet been written to exploit Windows 95, and prudent computer users won't install the new operating system until the bugs have been worked out. By this time next year, new versions of most of the software reviewed here should be available; until then, these programs probably will work best with plain old Windows. Macintosh users can use PIMs such as Claris Organizer (408-987-7000), Now Software's Contact and Up-to-Date (503-274-2800), or Attain's In Control (617-776-1110). OS/2 diehards can try Sundial Systems' Relish (310-596-5121). But let's face facts: Windows has triumphed in the marketplace.

Not everyone needs software to organize their lives. Lots of longtime computer wonks get along just fine without PIMs. If you're uncomfortable with computers, you'll be better off toting one of those Bible-size appointment books held shut with five or six dirty rubber bands, or possibly one of those silly personal digital assistants with keys the size of sesame seeds. And if you don't know anybody and never do anything, more software probably isn't what you need. But if, like many of us, you have both a computer and a life, a well-chosen PIM can help you master the quotidian details, freeing you to think large thoughts and experience profound emotions.

The sooner you start, the better. Transferring the complexities of human existence into a computer program takes even more work than you'd think, especially if you choose one of the most powerful programs. People who still keep addresses and other personal information in ordinary text files, created in a word processor, probably will have to reenter most of the data manually when they switch to a PIM. Here's a tip from CogniTech Corp.'s Sharkware Pro program, which self-help author and champion networker Harvey Mackay helped design: "Your contacts are your greatest asset. Enter the names, addresses, and phone numbers of all the people you contact regularly...Don't try to enter them all at once. Make a commitment to add four or five a day, and within no time your database will be complete."

NOT MINE. Working at the rate Harvey suggests, seven days a week, I would enter 1,825 contacts per year. My virtual rolodex, begun more than a decade ago, when most PIMs were too primitive to be of much use, is a sprawling collection of text files that probably contains 10,000 names and grows nearly every day. I'll never re-keyboard all that information myself, and hiring someone competent to do it for me would cost more than I'm willing to pay. Funny, until I had a computer I never realized I needed an assistant.

Resolving to buy a PIM is easy, but choosing one is like deciding whom to marry. The commitment is enormous. You're going to be spending every day together, and sustained compatibility requires more than a pretty face. That's the lesson I learned from Lotus Organizer 2.0, a popular, delightfully easy-to-use PIM that often comes pre-installed on personal computers. Its user interface, which mimics a notebook with tabs and loose-leaf paper, is gorgeous and intuitive. But Organizer's good looks conceal a superficial nature. The program's fancy graphics require so much computer memory that Organizer's alarms wouldn't work on my Hewlett-Packard subnotebook PC. This glitzy software will display anniversaries according to signs of the zodiac, but I couldn't easily figure out how to schedule an appointment that recurs every two weeks, or one that lasts less than 30 minutes. (Hey, I was an English major.) Organizer reminds me of the Jessica Rabbit cartoon character in Who Killed Roger Rabbit: totally hubba-hubba, but not someone you want to fall in love with, insofar as she exists in only two dimensions.

When a PIM is wrong for you, the effect is like being trapped in an elevator with the Jerry Lewis character from The Nutty Professor. He came to mind when I tested a heavy-duty program called PackRat 5.0--don't you love the name?--from Polaris Software. During installation, this powerful but prune-faced PIM failed to locate my computer's copy of Microsoft Office, because I hadn't put it in the directory PackRat expected. Once installed, PackRat displayed a pale-blue, gray, magenta, and yellow screen ugly enough to drive me out of the room before I could customize it. Even harder than looking at PackRat is figuring out what to do with it. To elucidate the relationships between program elements obscurely labeled "forms, categories and list viewers," an illustration in the program's manual shows what looks like a Cheez Whiz molecule, with artificial-flavor compounds sticking out every which way. On another page, the getting-started guide expounds: "The important distinction to make here is that forms exist independent of objects. Objects are tools that provide convenient ways to add and view the information in your forms but objects are not dedicated to forms." Sorry, Polaris. Life is too short.

For sheer incomprehensibility, though, the clear winner was Okna Corp.'s DeskTop Set, a powerful collection of PIM software that has been well received in magazines catering to the pocket-protector crowd. A Ukrainian emigra named Konstantin Monastyrsky created the program, and his picture is included in the manual: an interesting-looking fellow, probably someone you'd enjoy meeting at a dinner party. The manual also includes his charming dedication "to the hard-working and freedom-loving citizens of the United States." Unfortunately, that was about as much as I understood, although the text was nominally written in English. I never did figure out how to use Mr. Monastyrsky's widely praised program. ME, I'M the Ecco Pro type. What I want is the Robocop of PIMs, a muscular melding of man and machine powerful enough to impose order where mystery and chaos prevail. At the same time, I have a deep psychological need to preserve my independence, so I want software willing to do things my way instead of slamming me up against the wall and slapping on the handcuffs. Just as Robocop is a reasonable guy so long as you don't wipe out his family, Ecco permits you to customize its features nearly as much as you like.

Ecco's many components are thoughtfully designed and beautifully integrated. To set an appointment, simply use your mouse to drag a name from the address book to the calendar; at the same time, the program's contact manager will automatically file a note of the appointment. If your PC is connected to a telephone, Ecco will do the dialing for you and automatically log each call. You can store--and display--as much data as you want about each entry, in an outline format that happens to mirror the way I naturally organize information. And unlike some programs whose appointment books may start at 7 a.m., Ecco helps you work 24 hours a day.

Ecco may be the perfect PIM for me, but perfection comes at a price: The program is not great looking, and mastering its complexities requires a major investment of time. After months with Ecco, I still need to consult its manual and fuss with its countless scores of settings.

A less particular person might opt for Sidekick 2.0 instead. This program, from Starfish Software, reminds me of the Clint Eastwood character in For a Few Dollars More: It does what needs doing, without a whole lot of fuss. The program is simple to use--its manual is a slender 98 pages, vs. 420 pages for Ecco's--and is designed with deep understanding of what it takes to manage life in the late Nineties.

Sidekick is the personal assistant of your dreams on a single floppy disk. Its user interface--the screen displays and commands--is elegant and wonderfully functional. The address book is easy to customize, the cleverly designed calendar visually highlights multiday appointments such as business trips and vacations, and the program places a fast-access menu in all your other Windows programs. Compared with Ecco, which can slice and dice data any way you want, Sidekick seems limited--but it is probably the PIM best suited to the needs of most users.

For some people, even Sidekick might be more than they need. Back when I was making do with a homemade appointment book and rolodex in word-processing files, the closest thing to a PIM I used was Micro Logic's Info Select. This brilliant little program--recently released as a fully featured PIM but also available in the simpler version I use--gives instant access to totally disorganized data. The digital equivalent of Post-it notes, Info Select allows you to type in any random information you want to remember--your FedEx account number, Internet passwords, birthdays, cute stuff the kids have said, great Bordeaux vintages, whatever. Each entry gets its own virtual index card, and if you wish, you may organize the cards you store by category. I maintain one group for personal stuff, another for the office, a third for all the software commands I keep forgetting, and so on. Retrieving any card is easy: Just type in a word, or part of a word, that appears on it. Over the years, this program has proved phenomenally useful. Instead of trying to change your personality, Info Select takes advantage of the PC's robust processing capability, enabling even messy slobs to function as paragons of organization.

People who spend a lot of time on the telephone, yet don't want a full-bore PIM, should consider Phones 5.6 by Metz Software. Simple and efficient, Phones combines a good basic address book and contact manager with a sophisticated dialer that even handles those irritating alphabetical numbers, such as 800-GET-LOST. NOT ONE OF THESE PIMs is perfect. Software developers, please note: For people with more than one computer, it is unduly difficult to keep the same information up to date on each machine. Another area that needs work is speeding data entry. Whether you're noting information while on the phone or during the flight home from a business trip, you want to get it over with fast.

Ecco is on the slow end of the spectrum, while ACT! ranks among the fastest. Info Accelerator can automatically capitalize the first letter in any data field--a real boon--but it won't add a period to "Ms" or "Mr". Sharkware offers a helpful pop-up list for many data fields, automatically updating them with the information you type in. Once you create a record for someone at American Centerless Grinding Corp., the pop-up list of company names will always include it. But no PIM I tested could match the intelligence that enables Intuit's Quicken check-writing software to automatically fill in names once you've typed a few letters.

Sophia, please, let me know which program you decide to use. And if you ever need advice about telephone headsets, you know who to call.