Horror or romance

HERE!!!
bleach
D.gray-man
darker than black
black lagoon
hitman reborn
cowboy bebop
samurai champloo
ghost in the shell: stand alone complex
tekkaman blade +II
DB,DBZ,DBGT
death note
ghost hound
hero tales
afro samurai
hell girl
devil may cry
Kekkaishi
InuYasha
one piece
gintama
final fantasy: unlimited
Shakugan no Shana
Full Metal Alchemist
black cat

It's not really hard horror or romance but it's scary and absolutly not boring!!!
I like D.Gray-Man,Death Note and Shakugan no Shana the most!!

Elfen Lied has a lot of blood and guts in it. It's also really sad and has some romance in it.

Be warned though, it contains female nudity. A LOT of female nudity.

ToraDora or inuashia for romace

Trinity Blood, Blood + and Monster (espcially Monster) are pretty violent and in the horror catagory. Oh! I forgot Samurai Champloo too.

Inuyasha!!!!!!!!!!!!!!! and code geass

FullMetal Alchemist! If people losing limbs while trying to bring back the dead WHILE fighting the results of these failed attempts isn't scary enough, I don't know what is! There's also a bit of romance mixed in here and there, too!