Durarara!! I heartily recommend. You can watch it on Crunchyroll.
Black Butler (also known as Kuroshitsuji) has an extremely inconsistent tone and I'm told doesn't follow the manga, but the climax of the first season is great. The second season at least gets off to a strong start, but I never bothered to finish it. You can watch it on Funimation's website, I think.
There's some website that lists Mushi-shi as the #2 anime of all-time. I have two episodes left to watch and I'm waiting for it to get good. It's not bad by any means, but...zzz...you can watch it on Netflix Instant Play, if you have it.
I've seen four or five episodes of Deadman Wonderland. It has an interesting premise, but has seemed to be decent despite its efforts to the contrary. You can watch it on Crunchyroll.
Blue Exorcist (Ao no Exorcist) is an odd bit of fantasy shounen. Its first two episodes are action-packed and yet somehow dreadful. When it devolves into a high school drama with some fighting...it gets good. I don't get it either. On Crunchyroll.
One Piece...ahahaha. Good luck. On Funimation's website.
Darker than Black: Season 1? Good. Season 2? Bad. Suspenseful, action-filled...but not above filling half the episode with the boring half of the main character's life (sort of like Code Geass only less interesting). On Funimation's website, I believe.
The World God Only Knows: Damn that's a nice name. That's really the only thing I can say about the first episode, which is the only one I saw. It's on Crunchyroll.
Fullmetal Alchemist: Brotherhood: That one amazing thing now has an anime...again! Only now it follows the actual plot! Contains such notable figures as Evil Ziggy, Anime Hitler, and That One Guy Who Has An Adorable Baby Daughter. I think it's actually back up on Funimation's website, but if so, probably only for a limited time.
[C] - Control: Want to watch a premise tailor-made to be an amazing 500 episode long shounen action anime be condensed into eleven episodes? Then this is the anime for you! It squandered its potential, but the first eight of its eleven episodes are good. If you're still not convinced, it has a moe girl who eats money.
Yu-Gi-Oh! 5D's: Ahahahaha no I'm serious. Best YGO series in my opinion (an opinion shared by...few...people). You can watch the first 64+ episodes subtitled (which is the ONLY way to watch it) on Hulu. There's no need to watch after episode 64. Then it starts getting...weird. Like...really weird.
Cardfight!! Vanguard: Like Yu-Gi-Oh! except not as good and with less magical powers. Like...none, except something's implied. Watch on Crunchyroll. Stand up the Vanguard!
Death Note: I don't know how/if you've gotten through all that and haven't seen Death Note, but if you haven't, correct the imbalance. Just, after...something...happens, you can stop watching. You'll know what I mean when it happens. On Hulu and Viz's website.
Claymore: Girls in armor killing demons. The plot got cut off by executives, so it ends with a cauterized stump, but until then it's interesting. And that symbol looks kind of like the Geass symbol. Hm...*imagines them fusing* Best. Anime. Ever. Oh yeah, it's on Funi's website.
Code Geass: Do yourself a favor and watch it again. And again. And again.
Wow...that's a big list. Half of it was me saying everyone else's suggestions were bad, but...