Well I am actually bi already (LOL), but my answer would definitely definitely be Gocchin, of course^^ She is the most perfect girl in creation: talent, hotness, and cuteness all wrapped into one^^ And the fact that she's got great boobs doesn't hurt either LOL Also Aya Ueto... But that's no surprise considering she played that role in Kinpachi Sensei... *dies* ^^
Also Erika Sawajiri is pretty hot^^