I disagree very strongly with the notion of T9 being superior to QWERTY.
One of my favorite received SMSs was 'foot forget to give of a shout', sent by a T9 fan who didn't bother to proofread his messages. 😉
By far the most effective handheld device I have ever found for text entry (particularly anything beyond a few words) was the Psion Series 3c. The second best device? The E61. None of the many 10-key devices (either with or without T9), nor the many other QWERTY devices (Zaurus 5500, Psion 5mx, Mako (Revo), 6800, 9300, Treo 650, etc.), nor any of the touchscreen devices (same Zaurus, same Treo, various CE/PocketPC devices, various Palm devices, etc.) which I have can touch it, simple as that.
I became quite proficient at text entry with a 10-key phone keypad on the 6190, before T9 was an option. When I got T9-capable devices, I tried it, but it just never cut it for me. One of the first things I do when getting a T9-capable device is to turn it off. One of its greatest problems lies in its unpredictable nature, which is quite ironic considering that it is a predictive input scheme. 😉 T9 requires extensive proofreading, which contradicts any notion of increased speed, and/or makes it unusable (or at least highly inaccurate) without considerable visual attention. I have vastly more confidence in the accuracy of text typed on a 10-key keypad without T9. For speed and accuracy, a good QWERTY keyboard is the only way to fly.
Also, I tire of the complaints about QWERTY devices being so 'large'. The E61 is smaller than just the battery pack of a handheld cell phone of not too many years ago! It is also much smaller than many PDAs of even more recent vintages. Additionally, the E61 form factor is the closest to perfection which I have found yet, having no mechanical compromises in the form of flips, hinges, or slides, and also having an absolutely gorgeous display in the proper landscape orientation. Combined with a Krusell Classic case (a work of art in its own right), it is pretty much the ultimate device. Considering that it is smaller than a PDA, and replaces a PDA, a phone, and a variety of other devices, it is simply absurd to say that it is too large.