From what i've seen thus far, all of the current Nintendo 64 emulators for the Gamecube are just mediocre. I've used Project64 on a PC and was extremely impressed with the double resolution of the games and what appeared to be extra smooth framerate. Anyone know if this emulator might one day be ported for the Cube, that is, if the Cube is powerful enough to efficiently run the emulator?
It's strong enough, just no one's gotten around to making a great one. For now, the best one is the one that's used on the GameCube port of Ocarina of Time. Involves ripping the OoT rom out of it and transplanting a different one into it. Still, it doesn't work well with most games, but it's better than nothing. You aren't going to find any great N64 emulators for any current gen console though, as the Xbox doesn't even run all N64 games.