ToraDora's pretty good, but it's very bittersweet. Some other romcoms I think were good are Inu x Boku SS, Kamisama Hajimemashite (which is very similar to Inu x Boku), School Rumble, Baka to Test, and Clannad (which is also very bittersweet).
If you liked Ranma 1/2 you might also like Urusei Yatsura!
Baka and Test is pretty darn good XD It's more comedy then romance (though there is some romance in it) and it's also just super random and rather bizarre. But its pretty darn good, you should give it a shot X3
Toradora Nogizaka Haruka no Himitsu School Rumble Lovely Complex (this recommendation received the highly acclaimed A+ 2013 Best-in-Class holy $%@& seal of approval)
If you liked Ranma 1/2 you might also like Urusei Yatsura!
Toradora
Nogizaka Haruka no Himitsu
School Rumble
Lovely Complex (this recommendation received the highly acclaimed A+ 2013 Best-in-Class holy $%@& seal of approval)