Whats a fun class to play in WoW?

Ok i have a level 64 troll rouge really fun, But i want to make another class also that is fun. I made a blood elf paladin they are alright he's only level 14 . I made a human mage level 4 they seem ok . But from all of your opinions what would be a very good class and race and spec to go into. I want to make a caster and a tanker any ideas?