(FORTUNE Small Business) – It started with Los Angeles. I needed to get there and back, and quickly. So I called my travel agent, and she punched in my itinerary. About 96 seconds later I had an aisle seat on a major airline on the day and at the time I needed. Unfortunately, my ticket was about the price of a small foreign car. After gasping I asked, "Uh, excuse me, is that in lira? I did specify coach, right?" With no time to dicker, I begrudgingly booked the flight but muttered, "I should've shopped online."

According to my incessantly plugged-in pals, everything is better, faster, and cheaper in cyberspace. Armed with my laptop, a Net connection, and some residual anger from the thought of having paid too much, I vowed to log on and see if they were right. My conclusion? It often depends on your personal taste and timing.

The first thing you notice as you begin surfing is that virtually all travel sites require even casual shoppers to "register" with your name, e-mail address, and travel preferences. For privacy-conscious consumers, such disclosure can be discomforting. Cheaptickets.com offers this rationale: "Casual browsers are discouraged by the registration process..." It then adds, "Your profile information is private and will not be sold or given to others without your permission." Registering, the site claims, allows the company to customize its services.

There is some truth behind such marketing hype. Say you sign up for a destination and time that aren't available. If you've registered your e-mail address and travel preferences, most sites will notify you when your preferred itinerary opens up.

Another online advantage: You can log on as often as you want to get the latest deals. No one can adequately explain the huge disparity in airfares, but everyone agrees that they are constantly changing. But few travel agents want you calling them every 15 minutes. Online travel services prefer it if travelers check back every five minutes, since the more hits they get, the more they can charge advertisers. And while only the best traditional agencies provide customers with travel news and tips, most online travel sites routinely offer customers the latest weather reports, safety alerts, and currency conversion rates.

Here's a fast-fingered rundown of several online ticketing sites worth visiting.

AAA.com: Yes, it's that triple-A, the automobile people. It offered top-of-the-line info and rates once I got through. On two occasions the screen announced, "Sorry. That Web site is... probably too busy to answer right now...Try again later."

Biztravel.com: A little too bizzily designed for my taste, but easily a favorite for information access, low prices, and unusual money-back guarantees ("$25 refund when choice of entree is not available in First or Business class" or a $50 credit if you deal with an "unprofessional travel services associate.")

Cheaptickets.com: This 15-year-old consolidator (which buys tickets in bulk) is a good choice for last-minute flights. It was rated America's No. 1 Best Airfare Discounter last year by Frommer's Budget Travel, but I found some instructions confusing, especially those involving complicated, multileg itineraries.

Expedia.com: This is one of the few sites that allow you to shop for fares without having to first register. I also liked its clean, colorful look.

Lowestfare.com: I especially appreciated the easy-to-find toll-free numbers--for Internet Technical Support and Internet Customer Support--at the bottom of the home page. And you can easily restrict your search to nonstop flights only.

Travelocity.com: Along with Expedia.com, this may be the most popular online travel destination. It provides many consumer-friendly options, such as searching for cheaper flights departing from smaller, but still nearby, airports. Also, it will page you if your flight is delayed.

As you can see, I appreciate the appeal of online booking. It gives us civilians important morsels of data that once were unavailable. In dealing with a deregulated, increasingly uncontrollable industry, the best way to control your own travel destiny is to access an unfettered flow of information.

Yet if given a choice between asking a human being your direct (or even obtuse) questions and receiving immediate responses or...well, there really is no choice. For many frequent flyers (and occasional Luddites), travel agents are the only option. They offer a personal touch, not the least of which is that after, say, being bumped from a flight, you can simply call on the cell and rebook without rebooting or waiting on any line.

But when price is your ultimate concern, are the best fares found on- or off-line? We selected a few itineraries (domestic and foreign, hubs and small cities), then compared fares at several reputable sites and with a traditional travel agency, Navigant. As you can see from the comparison chart (page 118), there is no clear money winner. In all fairness, there probably are just too many variables, including the day and time you travel, the airline, the airport, how willing and able you are to make 11th-hour plans, how amenable you are to making additional stops en route, the alignment of the planets, etc.

Overall, no one can beat the fares that airlines offer, especially on last-minute flights. If your schedule is flexible and you can take advantage of last-minute specials, sign up for the regular e-mail bulletins offered by major carriers such as Delta and USAir.

The rest is personal preference. Check out the major travel sites. Find one or two that appeal to you--for aesthetics, customer service, incentive plans, whatever the reason--and begin your search there. Our contact at the Navigant travel agency, Ellie Garvey, even acknowledged: "The Web might be better for just booking flights" if, of course, price is your primary objective. The people who use travel agents pay a premium so they won't have to do their own research. Only you can determine what your time is worth. How important is saving a coupla (or a lotta) bucks? Some experts recommend the best of both worlds: looking online and booking with an agent.

My search for cheap seats never ends. Apparently, it just takes a lot of time to save a little money.