Hope some of these come in handy.
Kimi ni Todoke <= light, funny romance one, one you could watch with your g/f
Love Hina <= one of the best classic harem / romance ones
Amagami SS based on a dating game, each arc is an alternate reality where the main guy ends up with a different girl, it's like 6 romance comedy mini-stories with 6 different cute girls, i highly recommend this.
Asobi ni Iku yo! - <<boob warning>>, romance comedy, light action / sci-fi
Onegai Teacher - 18 y/o student marries his hot teacher - who is an alien. Obviously a comedy.
Zero no Tsukaima - earth boy sucked into fantasy world where cute girls at the magic school fight for his attention. Has some action balanced with comedy.
Denpa Onna to Seishun Otoko - futon girl. Really this is a show everyone should see just so you know what i am talking about.
Rosario + Vampire: human boy gets sent to a school for monsters many of whom turn out to be sexy girl monsters who all want the boy (LOTS of panty shots!)