Looking for cool anime series.

-To aru Majutsu no Index
-To aru Kagaku no Railgun
-Highschool Of The Dead
-Tengen Toppa Gurren Lagann

Nobody recommended mugen no ryvius yet, I'm dissapointed.

My votes:

Mugen no Ryvius

Gintama

Black Lagoon

Kamisama no memo chou

GREAT TEACHER ONIZUKA

Welcome to the NHK

MUSHISHI

genocyber
rahxephon
texhnolyze
serial experiments lain
boogiepop phantom
rainbow
steins gate
noein
FLCL
niea under 7
neon genesis evangelion
welcome to the NHK
great teacher onizuka
cromartie high school

What, no on mentioning Monster? What the fuck guys.

Monster. Detective, mature, thriller, action.
Hajime no Ippo. Boxing with great humour.
Clannad. THERE ARE NO BRAKES ON THE FEEL TRAIN.
GTO. Motorcycle gang leader wants to be teacher.
Aoi Bungaku. Bunch of short stories.
Berserk. Medieval fantasy with violence, great.
City Hunter. Comedic action, violence, underworld.
Golgo 13. Episodic action, this is something you can just pick up and watch without caring about story.
Nana. Drama.
Rainbow. After WW2, bunch of kids are sent to "special" school. Tough subjects.
Planetes. Drama.
Another. Horror, mystery.
Bakemonogatari. Can't really explain. Lots of witty dialogue.
Giant Killing. If you like football (actual football, not that murican handegg) then this is for you.
Seitokai Yakuindomo. Perverted humour, the best kind.

La Blue Girl

:P

Battle Angel Alita and Gunnm Last Order
Best mangas

Posting only those I have seen and can remember.

Hellsing TV and OVA, Chobits, Neon Genesis Evangelion, Angel Beats, Shingeki no Kyojin (second episode will be out today, but looks promising), Trigun, Bokurano, Sayonara Zetsubou Sensei, Tengen Toppa Gurren Lagann, Fullmetal Alchemist, Death Note, Darker than Black, Berserk.

Watch Puella Magi Madoka Magica, it's amazing.

Sword Art Online,
Accel World,

Both of these are fairly recent both have been renewed for a second season and both have their first season already done.

I'd also recommend HellSing Ultimate as well as the original HellSing, School Days, and Seins Gate. (Can't be bothered to spell it right.)

Bleach
One Piece

Someone certainly already posted Dragonball series, so yeah, that! And I remember one french anime (really) about some knights or something, including some greek gods and stars...it was VERY long ago so I don't remember a name but someone might:)

You watched both FMA and FMA Brotherhood right? If not, do so.

I'd add Sword Art Online, .Hack//Sign I would recommend. I also enjoyed Last Exile and Full Metal Panic!.

One Piece !!!

Katekyo Hitman Reborn was the only anime i've watched by complete, and it's a really good one too.

Aside from the ones you mentioned...

InuYasha (well balanced with nearly every genre)

Kaze no Stigma (well rounded with action, comedy, and a little horror)

Excel Saga (if you're looking for something really crazy)

Ouran High School Host Club (if you're looking for something silly and romantic)

Kimi ni Todoke (if you're looking for something REALLY romantic)

Fullmetal Alchemist: Brotherhood (especially if you liked the original series)

D.N Angel (haven't seen it in years, but from what I remember it was enjoyable)

Cowboy Bebop (a classic)

Soul Eater (haven't finished it, but it's awesome)

The Melancholy of Haruhi Suzumiya (great mixture of action, comedy, and a little action + romance)

My Little Sister Can't Be This Cute (similar to the one above, but less action)

...aaand that's all I can think of right now.

EDIT:
Oh yes, and FLCL! Epic anime!

Requiem from the Darkness

Captain Planet. The ultimate cartoon.

Death Note again :)

Ghost in the shell

Mirai Nikki, Fate/Zero, Kara no Kyoukai, Higurashi no naku Koro Ni, Shiki, Steins;Gate, Ao no Exorcist, Gurren Lagann.

Serial Experiments Lain if you're looking for something artsy and laid back. Some of the dialogue is underdelivered, but considering that most anime tends to overdeliver (which annoys me) I appreciate the difference.

Detective Conan. Doraemon. Crayon Shin-chan.

I recommend Tengen Toppa Gurren Lagann, Trigun and if you are into comedies The World God only Knows

Another is a great one.
http://myanimelist.net/animelist/Liboicl
Check out my list above. Anything rated at 8 or higher is a must see, in my opinion.

Shigurui, Ergo Proxy, Gunslinger girl, Last exile, Elfen lied, Berserk, Basilisk, Gungrave