I touch type. I think a large portion of techies and office workers touch type... I learned 15 years ago and it's hard-wired now. It's one of the problems I have with typing on the phone. Using T9 I don't have to click the phone key more than once, however I'm constantly searching for the letters on the keypad because they're in a different order all together.
Now, I know. The youngsters today are amazingly fast typing on the keypad. I could not BELIEVE how fast the guy who sold me my phone typed in some information during the setup. "clickety-click-click-clickety-click!" Amazing. However, my brain doesn't work that way. When I think "type p" my mind automatically starts my right hand moving and my pinky searching. However, on the phone, if I'm trying to type with both hands, the "p" is on the left under the 7.
So here's my idea - keep the T9 technology, but rearrange the letters to be in the same order as a qwerty keyboard. It would drive the non-touch typists nuts, but for someone like me, I'd be able to FLY typing on my keypad.
Also, Jacobo has expanded on the idea with a keypad based on letter frequency. (He's got an image, just in case you don't speak Spanish). The only problem is that different languages have different letter frequencies. So every language/country would have a different keypad. This goes for keyboards, too, I guess. There's no Ã± on my keypad example above but there is on my Spanish keyboard. ;-)