Some good stuff recommended so far.
I have a short list that I don't think anyone listed yet...
One Outs - it's a baseball/gambling themed psychological thriller
King of Thorn - sci-fi horror thriller
Kaiji - another psychological thriller
Rainbow - slice of life with a bit of a mature twist
Freedom - scifi post-apocalyptic dystopia, same artwork as akira and utada hikaru does the opening theme
That's about it but that's not to say I don't recommend anything else! Just that most were already mentioned; there's only so many times someone can recommend shiz like fullmetalalchemist/kenshin/evangelion/bleach/naruto/onepiece/trigun/cowboybebop/hellsing/ghiblifilms!
With that said, I'm currently watching Deadman Wonderland and No.6 and by 'watching' I mean I'm going to start watching them when finals are over.