joppu, The problem is that many games use all of the buttons on the n64 controller, and some just don't re-map well to a ps2 style controller. Lots of games are playable, but not all. I can't think of any examples of either right now, but that's just because I'm stoopid.
What would be REALLY nice though, would be a bluetooth driver for the PS3's sixaxis controller. That would cover just about any machine that could be emulated.
what i did before was remap the xbox controller with goldeneye similar to when i play COD 5 and it was a better experience than that of the PS2 controller.