Okay, I don't play as the Spy as much anymore, since everyone seems to have learned to give all their teammates a shotgun-to-the-face 'just incase'. Still fun to play occassionally, but it takes a lot of effort/patience... sometimes it's nicer just to rush forwards guns-blazing as a soldier.
Now I'm a born again Demoman... such a great class, can switch from offense to defense instantly. Very versatile. And what's not to love about a "black Scottish cyclops".
Oh, and the medic, too. It's nice being a support class sometimes, and you never really appreciate how important the medic is until you play a round without one. A medic with an ubered soldier or heavy can completely break a boring stalemate.
My steam username is Dextrous.