I bought myself an iPAQ 3975; it was about the first PocketPC with built-in Bluetooth.

The thing I wanted most was to be able to use Bluetooth to connect to the Internet via my phone, and it accomplishes this quite nicely. I can look at maps in remote places. I can hit Google and Pricewatch when at the computer store to ensure that I'm getting a decent price and buying something compatible with alternative operating systems. I can use ssh to connect to my home machine and make changes or check in with friends via console-mode ICQ.

The ClearType font smoothing is nice enough that I'm finally using a PDA for reading books, as well. I carry around most of Project Gutenberg in my back pocket, and I'm never at a loss for something to do when waiting on a bus, a flight, or killing a little time between meetings.

The Tungsten can browse the web, however not as many pages are compatible with its browser. Similarly, there are some book offerings, however the display doesn't seem as nice, and it supports fewer book formats.

If neither of the above interest you, and you're only worried about appointments, names and addresses, then even the Tungsten might be a waste of money. There are lower-end Palm devices available for only a hundred dollars or so.

If you prefer to avoid Microsoft, if you have a particular affinity for the Palm OS, or if Windows isn't your primary desktop at work or at home (Mac and Linux users will have trouble synchronizing a PocketPC from the desktop), do look at the Sony Clie devices. Sony has models with much brighter, higher-resolution screens than the Palm counterparts at about the same price. The Clies don't have as substantial a feel to them, however... so there may be some research to be done with regard to their ruggedness.

And... that's about all I know.

Good luck!

I've not done more with Sony or PocketPC devices than pick them up at POS displays and look at the industrial design, so this is purely from a Tungsten T users POV. I do use the Tungsten T daily (hourly?) however, so here's my take on it.
First, a couple of counterpoints to the above:
Web - The T includes both an HTML and a WAP browser (There's also 3rd party browsers out there). I've never had any trouble rendering sites (except for those obviously formatted for larger screens - I would imagine the PPC has the same issues). Admittedly, I havent tried any flash-laden showoff sites - Most of my handheld surfing is on Slashdot, The Onion, weblogs, the occasional Google or IMDB search and online banking (the included browser does support HTTPS transactions).
E-Books - With the included sofware, Palm can display; .DOC, .PDF, .TXT, .HTML, and Palm's own very popular e-book format. The only major missing e-book format is Microsoft's .lit, for which I've not seen a whole lot of content (much less _exclusive_ content). Anyone who wants their e-book to be read will publish it in a Palm-compatible format (except maybe MS :)
SSH - There are several SSH clients out for the Palm as well (and both Palm and PocketPC have VNC clients too!). TopGun SSH is the one I use. Not something I'd want to do serious script editing in, but it's plenty adequate for a portable SSH client.

Bluetooth - I use the T with both my Ericsson T68 and with BT access points located throughout the office tied into our local LAN. General connectivity is pretty sweet - the BT is plenty fast for pulling down content to fit on the small screen. I've also downloaded .PRCs directly to the device and started using them immediately - very cool!
You do have to set up specific connections for each BT reciever (BT is not designed for 'roaming'), so as you switch from AP to AP, you have to change connections in the network panel - maybe someone will write a quick-change applet if BT catches on.
The connection via phone is seamless once you set it up. Included is Windows based Phone Link Wizard, which goes up to the net and grabs the latest phone drivers, which then walk you through (on the device) setting up access. I did stumble a few times, but now that it's there, it works flawlessly. You leave the BT on the phone on by default and you dont have to touch it at all to create the connection - just leave it in your pocket/briefcase.

Sound - Tungsten includes a built in speaker, headphone jack, mic and voice-recorder app. The TI OMAP processor supposedly has a built in DSP for audio and such. The built in speaker's only really decent for playing back voice, and even that's iffy. The headphones are miles better. There's an MP3/OGG player out there that sounds resonably good, although you need an SD card to store music. Even though the T's got good audio capabilities, most apps don't use 'em to maintain compatibility with legacy hardware.

Size-wise - I migrated from an m515, which is just a bit thinner. Thinner enough that I had no troubles sticking it in jeans-pockets all the time. The T's just a bit too large for 'all-the-time'. Maybe I need to switch to khakis. The sliding thing's a bit of a gimmick, I find it's more useful for its functionality of turning the device off and on, rather than that of making the device bigger/smaller.

SD - Software can be stored on the SD card and most database-oriented apps support storing DB's on the card while the app itself lives on the device (IE - E-Books, PDF's, images, mp3's, etc.)

D-Pad - The 5-way pad is really nice. Has a good solid feel to it and works well with legacy apps. It can also be used to navigate the launcher. I've always thought the lack of good directional (left/right) controls really killed the Palm's abilities as a game platform, I've played a few new games that use the new D-Pad and it makes all the difference in the world.

Battery Life - I can't comment too much on this, as the device sits in the cradle when I'm at my desk. I've spent an hour or so straight surfing via BT and only used a sliver of the battery gauge.

As for look/feel and screen, I suggest going to a store and checking it out in person. I've found those two items to be very subjective.

Hope that helps. Feel free to email if you have any questions or arguments.

First things first — it looks like Palm is dropping Grafitti ( http://www.macobserver.com/article/2003/01/14.14.shtml ). Would this impact your decision at all?

Myself, I've gone through two Palm-OS devices — an early Palm that I can't think of the model number for, that I stopped using when it stopped working (no idea or explanation why, it just quit, and no amount of resetting or battery replacing made a difference), and a Kyocera phone/Palm combination unit that I never bothered to turn the phone side on for, and stopped using when I got my iPod.

I found that I rarely, if ever, really had a need to enter anything into my Palms. 95% of the changes I made to my schedules, contacts, or whatnot were done on my desktop and then synced to my Palm, and practically all I ever used it as was as a read-only device. Once I got my iPod, I found I no longer had a need for the Palm — the iPod syncs with my Mac's address book and calendar, so I had all that information with me at all times. If I ever need to get information when I'm out in the wild, I'll just grab pen and paper and jot it down until I can get home and put it in the 'puter.

So for me, at least, the iPod does everything I used a Palm for, plus I get 10Gb of music and/or file transfer space. Just the option I went with, of course — as always, YMMV. ;)

Wow! This is why I love the blog-o-sphere! Thanks for all your input above, guys!

Palm dropping Grafitti would definitely be bad news for me, as my handwriting is barely legible by myself, practically not by any other humans, and therefore, I suspect, not at all by any computer giving it a try. Maybe I should "train" my "jot" software to read Grafitti instead? ;-)

As for the heavy focus on BlueTooth and net-surfing above, this would probably not be my primary uses of the device, so I'm not entirely sure that that would be the deciding factor.

I definitely want:
- name & addresses (not just read-only -- I add most through the PDA)
- calendar (same as above)
- THIN AND LIGHT (must be thinner than my old PalmIII (prefereably a lot thinner; which has kept me away from for example the iPAQs)
- reasonable memory capacity (e.g. for project gutenberg books etc)
- IR synchronization if possible (since I always lose the cables I'm carrying around)
- bells and whistles (just because... ;-)

Based on the above criteria, maybe you should look into the m515 instead. It's thinner and lighter than the Tungsten and ~$200 cheaper. The only thing that the Tungsten has over the m515 for the above needs is the high-res screen.
While the difference is certainly night and day between the T's screen and the m515, I had no problem reading many large books on the lower-res screen. Like the Tungsten, the m515 takes SD cards, so storage isn't really an issue. (FYI - I see where Costco has 128mb SD cards for $46!)

The m515 also has a great flip-cover to protect the screen, something that the Tungsten sorely lacks - it's got a plastic cover, but it's a snap on thing that's much more cumbersome than just flipping a lid open (think dealing with a lense cap versus opening a paperback).
To be honest, the bluetooth was the only reason I migrated.

If you're talking about buying now, the Grafftti thing isn't really an issue as it'll still be in the shipping devices. Given that there's some 20 million devices running "old school" Grafitti, it's unlikely you'll see a dearth of incompatible apps being developed.