Logiclul said:
I've only seen two:
Death Note
Code Geass
I loved both of them, but I also know that I would hate any anime that doesn't possess some psychological aspect, some intelligence quota or complicated yet masterful plot (I don't really know what I'm describing, other than Death Note and Code Geass).
My friends have mentioned two animes to me and I can't decide to watch one of them next or something completely different:
Baccano!
Higurashi: When They Cry
I haven't looked at anything more than an introductory paragraph for each because I'm afraid of spoilers, and it's too late at night to call my friends.
Suggestions? (also one time the captcha gave me four diamonds... what the heck?)
By the sounds of it, it seems like you prefer the more action packed and/or smartly done gore fests. Fine by me!
Perhaps you could try Ergo proxy for a smart pretentious dystopian drama
Deadman wonderland for a more supernatural dystopia.
Mirai Nikki for a sci-fi-ish dystopia, warning- The main character starts off as a massive ******, and WILL get on your nerves, but he mans up later on (It's ongoing, so not all the episodes have been released, it's on episode 11 at the moment)
Also a very unknown one is an anime called Speed Grapher, you'd love it if you loved death note, it's very similar in a lot of ways, but has more action.
But if you want anime, just go onto any anime site and look at some rankings. It will sift through the rubbish and the gems for you, enjoy!