Considering how much you use the bloody thin, I think that it’s fair to say that you want a phone to be as comfortable as possible. There is a definite push in the marketplace toward thinner profiles, but these may not provide the best in ergonomics.
Designer Heikki Juvonen has concocted an interesting Nokia cell phone design that is simultaneously slim and ergonomic. Instead of s flat bar, the phone actually has a unique curvature to it. This allows the phone to be better cradled in your hand as you go through the dialing or text messaging process.
The design concept places the majority of the weight in the lower half of the phone as well, so when you hold it in your hand, the handset will be weighted near the bottom, adding stability. A top-heavy phone is one that easily falls out of your hand.
As unique, interesting, and ergonomic as this cell phone design may be, I don’t think it’s quite as well designed for actual talking. By adding that S-curve to the profile, you are actually taking the microphone portion away from your mouth. Contrast this to the “banana”-style curved sliders that Motorola has been trying to release lately.