Name one that isn't either hobbled with poor hardware or poor interface. Or one that is really hackable.
The Archos Internet Tablet almost hits the sweet spot for me... but even the Android implementation on it is neutered and not fully open.
I want something that takes the phone form factor, but whose primary purpose isn't phone. The iPhone/droid/touch of the world are nearly that but sadly tied to a carrier.
Think slightly bigger than iPhone, smaller than CrunchPad. Big enough to be useful but small enough to pocket and have with you at all times.