newb
my favorite is hard to say, but it's either Angel Beats or Kino's Journey
The reasons I like Angel Beats are obvious; it's made by freaking Key animation. This was their last project before they split, so they were at their peak here. Visuals, soundtrack, story, and action were all freaking fantastic. (Also one of the few anime to have a better dub than sub)
Spoiler!
Now for Kino's Journey, it's much more laid back, and it's made by a smaller company. In all, visually, it's not that impressive. What sets it apart is it's mood. It's kind of impossible to describe it, you just have to go see it for yourself.