I just want to note that I don't endorse emulating. It's generally a good idea to buy the games. But after messing around with Dolphin, I feel that if you use an Xinput controller, you get the same experience that you would with the actual thing, minus a few slight differences (ie. Super Mario Sunshine, where you can't run and shoot water at the same time.)
This is definitely cool technology, though, considering how hard it must be to program. GameCubes have PowerPC processors, and if you've ever tried using a pre-2006 Mac... well, you know. Compatibility and stuff.