Vanilla: Hunter --> Warrior
Tbc: Paladin
Wotlk: Paladin(Nax) --> Priest(Uld,TOC) -->Paladin(TOC,LK etc)
Cata: Paladin -->(Bot,Tot4w,Bwd) Shaman (FL)--> Rogue(DS o.O.)
Mop: Paladin
I enjoy playing my paladin quite a bit. I've mainly switched in the past xpacs because of need for our raid comp.