neon genesis evangelion is the greatest anime series ever. just.. startling.
obviously, i like all the ones everyone lists.. flcl, bebop, akira, excel saga, paranoia agent, ghost in the shell, perfect blue... obvious ones. pretty much anything released by manga entertainment is worthy...
adult swim is surprisingly adept at picking good anime to show (which is interesting when you consider all the shitty comedies that last 5 or 6 episodes that they constantly churn out and their fans pretend to like).
if you like flcl, check out dead leaves. it's even CRAZIER.
another crazy show.. i forget the name of it.. something something school.. damn what's the name..
www.tv-links.co.uk has a ton of anime to watch (including blood+ .......... and SAMURAI PIZZA CATS!!!!!!!!!!!!)...
oh and i may be the only one, but i love super milk chan.
EDIT: i replied to this thread before i read
umjammer atomsk's post.. CROMARTIE HIGH is the show i was thinking of.. i watched a fansubbed version of it when it was called [something something] cromartie high school and loved it. Also surprised to see someone else who's seen Dead Leaves. And is your name a reference to um jammer lammy? ... I feel like a dork. I'm going to c check out the series you suggested that I haven't seen.. also, the pillows - last dinosaur is such a great song, and i did a cover of ride on shooting star a long time ago..