Well, there's the difference between 2D/3D gameplay and 2D/3D graphics. As far as I know, Kirby 64 is 3D graphics-wise, but I may be wrong.
Anyway, on topic: I like many 2D games, and I love sprite art, so I'll go with 2D for now. However, I'm interested in the "new" 3D, or at least in some...