Recommend me a Anime.

Some of my personal favourites are

Chrno Crusade
Full Metal Panic series
RahXephon
S-CRY-ed
Steel Angel Kurumi series

Death note, hellsing ultimate or sword art online

Search the forum, tons of threads with some good suggestions in them.

Boku no Pico

If you haven't watched Steins;Gate watch it now.

Death Note

Naruto

Bleach

One Piece

Full Metal Alchemist

death note

naruto + naruto shippuden

bleach

clannad + clannad after story

sword art online

Another

gurren lagann

Baka & test

Little busters

These are some good animes from the top of my head

BECK

Death Note and Fullmetal Alchemist

Naruto is alright, but not 100% recommended

upcoming anime

Hen Semi

The Melancholy of Haruhi Suzumiya, skip the Endless Eight episodes in Season 2 though.

One Piece!

Tengen Toppa Gurren Lagann ^^

oldie, but awesome, Great Teacher Onizuka

Mandatory Ranma 1/2 suggestion.
And... yeah, pretty much search "anime" on the forum and you'll get LOTS of threads with possible suggestions.

Sakurasou no pet na kanojo
Seitoaki No Ichizon
Gintama
Sword Arts Online
K-On
Lucky Star

akira, ghost in the shell, ninja scroll, fist of the north star, neon genesis evangelion, gunsmith cats, space adventure cobra, the lensmen, cyber city odeo 808, robotech, macross, patlabor, appleseed, the castle of cagliostro, porco rosso.

First tell us what you LIKE. Otherwise you will get 50 people shouting Bleach, Naruto or whatever the hell junk is popular at the time.
Scifi? Fantasy? Comedy? Serious?

Just some random ones I enjoyed recently:

Stein;s Gate, Mirai Nikki, Another, Bakemonogatari, Kara no Kyoukai, Welcome to the NHK, Ao no Exorcist, Fate/Zero, Serial Experiments Lain.

steins gate , Angel beats - do it !

Soul Eater.

Sword Art Online :D

-Saikano
-Steins:gate
-Fate Stay Night (movies and series)
-Gai rei Zero
-Elfen lied