4. Mystique
What's hotter than having a sexy blue girlfriend that can morph into any one you want her to? She's the ultimate girl and there's no way you'd ever feel the need to stray. Hot new girl in the office? Mystique can easily become her to help satisfy your interest. Can't stop thinking about the latest Playmate of the moth? Easily solved. Just make sure you allow her to keep her true form once in a while in case she gets pissed off and refuses to play along anymore. And let's be honest, if she chose to stay blue it wouldn't really matter as she's red hot as she is. Mystique is every nerd's wet dream woman. Be careful though, she's a killer in the bedroom ... or so we're told.