I couldn't possibly resist taking a Geass myself. I think I would want one that freezes time or slows it (without uh, like, stopping your heart. xDD) if only for my own leisure, because I have no real ambitious goal involving fighting. That might get boring after a while, though, so maybe a laser Geass like Lelouch's. step two I go crazy and kill a crapload of people in mecca

Or I might not want one at all. I don't know. To be honest I'm content to just sleep and read manga all day. ;_;