(FORTUNE Magazine) – The airport security guard already thought me a fool or worse for trying to slip past him with a deadly set of fingernail clippers concealed in my overnight kit. But when he asked to inspect my backpack, I got nervous. First he pulled out my laptop, my cell phone, and my Palm personal digital assistant. The pile grew larger with power adapters, batteries, battery chargers, power cords, a flashlight, an Ethernet cable, noise-canceling headphones, a couple of DVD movies, a portable MP3 player, a digital camera, and a tin of Altoids. "Do you really need to travel with all of this...stuff?" he sneered.

Well, maybe not. Starting this month, I'm going to reduce the pile by at least a half-inch or so by packing the new Handspring Treo 180.

The Treo 180 is an ingenious new communications device that combines a cell phone, a PDA organizer, wireless e-mail, SMS messaging, and Web browsing, all in a remarkably slim, gunmetal-blue package that's smaller than even the smallest current Palm organizers. The Treo 180 includes a tiny Qwerty keyboard, the same size as the one used by the popular RIM BlackBerry e-mail device--which is to say, Barbie-sized--and has a small but usable monochrome touch-screen display. It costs $399 with service activation ($549 without) and weighs 5.4 ounces. Dollar for dollar and ounce for ounce it's the most useful gizmo I carry. I haven't been this enamored with a new gadget since Palm's original Pilot PDA, which is fitting because the Treo comes from the same designers.

That's not to say it's perfect. The 180 is the first in a series of Treo communicators that Handspring plans to introduce this year, and it's a work in progress. The phone is based on the GSM 900 and 1900 wireless phone frequencies. GSM is the global standard everywhere but the U.S., and while calls were clear and reliable when I tested it in several cities using VoiceStream's network, GSM does not yet have the same wide coverage areas as the more popular CDMA and TDMA systems. In theory the Treo will work in Europe and Asia.

The e-mail system is adequate for consumers but not for corporate users, at least until a secure mail system is offered. It works with POP3-compliant mail systems and requires only modest tinkering to work with AOL Mail and AOL Instant Messaging. SMS messaging, the sending and receiving of short text messages on a phone, is phenomenally popular beyond the U.S. but still a curiosity here. The Web-browsing features are limited by screen size but are surprisingly handy, if you can wait a minute for Web access. The rechargeable lithium-ion battery promises 2.5 hours of talk time and 60 hours of standby, although mine fell a bit short.

Still, clever features abound. The phone includes a speed-dial system, a speakerphone, three-way calling, call waiting, a call-history log for retrieving phone numbers, and--at last!--a simple on-off switch for turning off the ringer in places where phones ought not to ring. The built-in phone book can be populated from a Windows-based computer's Microsoft Outlook contact list (Mac OS X compatibility is pending), along with Outlook's calendar, to-do lists, and memos. Pressing the first few letters of the call recipient's name on the keypad almost always brings up the right number for touch-and-tap dialing. The Palm OS adds expense reporting, a calculator, and other handy travel features, along with access to hundreds of Palm-based programs and games (the Treo has 16 MB of memory). A jog wheel on the side makes one-handed operation easier.

It all adds up to the best "smart" phone yet, and it's going to get better. People with larger fingers may wish to try the 180g model, which replaces the dinky keyboard with a Graffiti handwriting system familiar to Palm and Handspring users. A color-screen version is coming at midyear for $599. Handspring says it will eventually offer a CDMA version, which will expand the choices for wireless service beyond VoiceStream and Cingular.

Best of all, the Treo can be upgraded later this year, via software, to GPRS (general packet radio service), as well as to a "push" e-mail service that will automate the delivery of mail to the Treo in the same way that mail is sent continually to a BlackBerry. For now, Treo users have to dial in to retrieve their e-mail. GPRS is up to three times the speed of the 9600-baud GSM service, which will make Web browsing a nice way to pass the time while you're waiting to be frisked at the airport.

Feedback? technology@fortunemail.com