The Dark Knight.
Because Vegeta never cared about him all that much I guess. Also considering that Vegeta was the one to kill him there is no way Nappa would have stayed loyal. Even if he did, by Namak Nappa would have been a weakling, which Vegeta would have no tolerance for.
I got about half way though Mushishi and just stopped. I am not sure why, it's unique and really good. If your into Mushishi I would highly recommend Kino's Journey.
Because Japan isn't a victim of Animation Age Ghetto.
This is part of it. In North America animation is either aimed at children or are adult comedy's. I am a fan of animation as a art form, I love the look of something animated. It has a certain quality that is lacking in live action movies/shows. Anime offers more diversity. For instance you would not see something like Usagi Drop in North America.
@Bigheart711: Yeah, but in her case that is the joke.