Just be sincere, and relax! The rushees will probably be far more nervous than you! Try and deviate from the standard questions, they were boring then, and they still are. Have interesting conversations, it'll make the rushee and your house more memorable.
As for pref, I know what you mean by cheesy (sp?). I find it easier to talk about why I think she'd be a great addition etc, than to ask her, and keep her from the awkwardness of "umm, no I don't feel at home!"
------------------
Travelling with no boundaries, moving in imaginary.