Just saw Blade II yesterday.. it's quite a good movie. I'm voting for a night out movie even though I was a cheapass and went to see the matinee.
Parts of the (extremely cool and well coreagraphed [spelling? Eh.]) fight scene were a little off with the CG, though.. Maya is *not* for showing intricate full body movements. Other than that I couldn't find anything really wrong with the movie.. Guillermo Del Toro is a sick, sick man.
If you like action, martial arts or otherwise, and either can stand or don't care about blood, definantly see this movie. You'll like it.