Akira is amazing! and it's really the only comic I've truly paid attention to so far (although when I was about 15 I read spawn...). They just released the final two parts (9, 10) here, but I haven't purchased them yet.
I borrowed last year a few sin cities from the local library but, even though I love the art, I wasn't too fond of the characters and plot lines. From the sadistic aspect they're cool though.