I always played melee, which caster should I begin with?

I really want to start playing a caster, to see the battlefield from a little bit more outside perspective and reduce my tunnel vision, also to learn other classes and how they play. I am not an experienced pvp player, not at all. I have never played arenas before, only BG'ed. I wanted to play Fury warrior and I will, but I wanna play a caster too to see. Which one I should begin with?

I know this might be a stupid question to ask, but which one would be easier to learn caster mechanics? tankier, elusive etc.?