This is a tough one. Overall all things considered I'll go with Chinese. It definitely has the biggest variety.

Second is Japanese. I'm not even that big a fan of sushi, but I love ramen, udon, Japanese curry, and even their take on western dishes

Third is Korean. Korean BBQ may be one of the best ways in the world to eat meat, but I'm not as big of a fan of their other traditional dishes.

Fourth would be Thai because I love Pad Thai. Fifth Vietnamese. Haven't eaten enough of the rest to form a strong opinion