Awesome Dark and Stylish Anime

[Darchrow]

Mahou Shoujo Madoka has already been suggested but I'd suggest it again, it is very stylish thanks to shaft working on the project
Serial Experiments Lain is a bit old so might be drawn off by the art style
Steins;Gate a newer series but its very good so far
Texhnolyze very slow start picks up after the 5th episode so I find it a bit hard to recommend
Higurashi no Naku Koro Ni Basically break the cutie over and over again
Le Portrait de Petit Cossette very short but I loved it - 3 episode OVA
Kara no Kyoukai: Garden of Sinners high production anime with VERY good animation its semi-movies about 50minutes in length.

 

[aznj03]

Higurashi
okami kakushi
phantom: requiem for the phantom
Shiki
ga rei zero starts good

the following are maybes
trinity blood
xxxholic
darker than black
durarara
ghost hunt
claymore
blood+

and i think everything else would be more repeats

 

[Evaheist666]

Gantz
elfen Lied
Ergo Proxy
Neon Genesis Evangelion
Paranoia Agent
Boogiepop Phantom
shigurui