Japan. I'm a huge fan of most things Japanese: martial arts, ninjas, godzilla, anime, cosplaying, Buddhism, the works.
I know many of the places I'd check out: Mt Fuji and the forest of suicide, Iga Ueno city for the annual Ninja festival, Tokyo, Hokaido...
It just always seems like an interesting place to stay. Plus, I got all this knowledge of Japanese etiquette that would be otherwise wasted.