art recommendations.

Stuff that looks good consistently. Plot, dialogue, etc are irrelevant.

Hellsing did this. Elfen Lied did this in some episodes. Berserk does this often. Texhnolyze is based upon this. Serial Experiments Lain defines this. Cat Soup defines this.

The anime named are beautiful, and I'd love to see more like them.

i second the motion for Gankutsuou.
Last Exile is another that hasn't been mentioned yet.