Verizons Voyager
The only thing that "wow'd" me about this phone, was it's desgin. But it's safe to say that the Voyager is the best PDA Verizon carries.
Blackberry Pearl
Blackberry is a word that everyone associates with PDAs. The Pearl has been out for about 2 years now, and AT&T just announced they will be selling them to new customers for only $29.99. This was one of the first phones I ever had, and I find it unbelievable that they're selling it for that price. Blackberrys have basic features all PDA's should have, and unlike the Pearls big brothers, the Pearl comes with a 2.0 MP camera. The Pearl navigation on the phone is original and works suprisingly well. The phone is good for emailing, texting, web browsing and that's about it. The only downfall I could find for this phone was there isn't a whole lot of personalization.
Moto Q
The Moto Q through Sprint slipped through everyones radar with a really bad launch. There's nothing really wrong with the phone. It runs off of Windows Mobile 6, and has the basic features of all the other PDAs (1.3MP camera, basic web viewing, email, ect..). The only thing I didn't like about this phone, it was built for a guys hand. I had issues holding it.
Pantech Duo
Pantech isn't a very respectable name when it comes to cellphones, they're mainly known for making inexpensive pay-as-you-go phones. The design of this phone is possibly one of the best, with the qwerty keyboard and then the slide phone for actual dialing. But I'd be worried about durability -- since I'm pretty rough on phones.
PalmOne Treo 700wx
Apple's Iphone
Enough said.
Samsung BlackJack II
I think I'm saving the best for last. After looking at multiple phones and features, I went with the Blackjack II. Like the Moto Q, it runs on Windows Mobile 6 -- Which allows you to edit (Not just view!) windows files from the phone itself (spreadsheets, excell, word). If you ever get a chance to get your hands on it -- I highly recommend just playing with it for a few minutes. It's a great phone, and only $79.99, with a two year contract! Plus it's one of the few PDAs that didn't take away the mobile gaming feature (Blackberry's Paddle Ball game doesn't count!).