I have to say this at least once. Tekkon Kinkreet is really impressive and is, what I feel personally, the animation with astonishing art direction and outstanding visuals. To be convinced, see here. It was originally released for theaters in 2006, and its English DVD edition is scheduled to be released on 25th Sep (buy *cough* me one).

Tekkon is directed by Michael Arias; Original manga by Taiyo Matsumoto; Art direction by Shinji Kimura. More details here.