I saw videos on YouTube where Metroid Other M was played with the Xbox controller. I also watched a video someone playing Goldeneye 007 on Dolphin using the XBOX 360 controller. What other games support the controller?
Dolphin can emulate a wiimote with any controller, so all games.
And all games that support GC controller will support the 360 controller as well.
If you want to emulate a Wiimote with another controller, it'd be quite annoying to press a special button for "shaking" or "swinging", just warning you...