After weeks of considering different phones, including the new T-mobile Dash and latest Samsung BlackJack Windws Mobile Smartphones, we decided on the new Cingular 8525 with Windows Mobile 5 Pocket PC Phone Edition. (CNET has a review of the phone here.)
We both like the form factor of the Cingular 8525 (also the HTC Hermes) and the feature set: the 400MHz processor and 64MB of RAM, bundled Office Mobile applications and Windows Media Player 10 Mobile make for a good customer experience. The unit is supported by Cingular's 3G network, and I've seen the difference this week in sync'ing email and web sites. The support for both Wi-Fi and Bluetooth 2.0 is very solid, with my BT headset and USB adapters working right out of the box.
The ergonomics and design of the device is good and feels solid in your hands, and the key travel for thumb typing is IMHO better than I found for my fingers on the Dash or the BlackJack: controls are easy to use and access. And as it's essentially a Pocket PC, I find that the addition of a stylus and touch screen makes it easier to navigate around.
The clincher on this deal? Over the holiday shopping weekend last week, Cingular offered a "Buy One Get One Free" deal and the phones were essentially half price: not only was Cingular's family plan comparable to what I had on T-Mobile, their pricing on devices was better. (The lowest tier of Internet access is a couple of dollars more a month than T-Mobile's WAP access, but affordable.)
Also, we both like the 2-megapixel camera, which takes nice shots and is easy to use.