What's your favorite class to play?

Since I hail from the SPUF-TF2 forums (Steampowered users' forums, TF2 section) I've taken it upon myself to post the first thread in the Team Fortress 2 Polygon forums! Yay!

Anyway, what's your favorite class to play? Not necessarily the class you're best at, but the class you enjoy playing the most.

For me, it's probably between the Scout and the Demoman. I'm really great with Soldier but he's just not as much fun as Demo and Scout for some reason.