If I may just reiterate a point that was brought up by a few forum members previously, I would really really prefer a T9 phone keypad with predictive input over a mini-qwerty keyboard in portrait mode. The keypad that I have in mind is something similar to what is already found in symbian s60 v5, except.... please take away the obtrusive interface that fills up the entire screen, and let the keypad slide up from below in an iphone or htc winmo style to occupy the lower half. I think a phone keypad is excellent for short quick inputs with one hand when I reply an sms or add a new calendar event, while the dedicated hardware keyboard is optimal for typing an email with both hands.

I think an elegant solution to the non-uniform UI problem with the support of both portrait and landscape modes is to make everything landscape by default, and rotate to portrait only when keyboard is closed AND the phone is rotated such. It is an interesting take of the conventional phone with hardware qwerty whereby the phone is portrait by default and turns to landscape when keyboard is slid out