I don't mind the D-Pad on the N800 but it is a bit stiff. I think the best thing for gaming would be a tactile mini joystick (like on the PSP). You would get the advantage of a D-Pad and joystick together, plus you could press down on it for the button.

http://upload.wikimedia.org/wikipedi...m_%26_lite.png
The knob in the bottom left corner.