Here's a list of some of what I have watched already. If you like romances, I suggest all of these to watch. But be warned that some of these do contain ecchi things; fan-service. Also be nice if I could get some suggestions on what to watch next. ^^
Watched:
UFO Ultramaiden Valkyrie
True Tears
Seto no Hanayome
Utawarerumono
Gift ~Eternal Rainbow~.
Ouran High School Host Club
Peach Girl
Fruit Basket
Love Hina
Kanon
School Rumble
Please Teacher...
Lucky Star
*REC
R.O.D.
The Melancholy of Haruhi Suzumiya
Aishiteruze Baby
Lovely Complex
Karin
Rosario + Vampire/Capu2
Rurouni Kenshin