I prefer to play the girl....

SamuraiXSamuriai
VampireXHuman
DemonXAngel
AngelXHuman
CousinXCousin
GangXGang

Here are some anime I'll do....

Shugo Chara: AmuXIkuto or AmuXTadase
Inuyasha: KagomeXInuyasha
Gakuen Alice: MikanXNatsume or MikanXLucis (sp?)

That's stuff off the top of my head plus I don't care doing more than one XD