If you like Paladins try a Bear Shammy - it's melee + heals but they are rather weak below level 30
ToS is a healer + caster and they are probably one of the best AoE class in the game(if not best), watch out they are getting a hug nerf in the next patch which is necessary
PoM - like NoR said but they also have the best CC's in the game.
Necros - they are crazy fun. You can run Pets or spec Nightfall for better Dot's and nukes. Very easy class to play and deadly in pvp + pve.
Demo's - Squishy mage type caster. They have good CC's, great AoE, and are the #1 DPS in raids.
HoX - They are mad fun. A great combination of Melee and Casting. Very high dps but wear cloth and tend to be squishy.
Guardian - The standard tank
Conq - Good damage, able to take a hit, makes a good off tank. Can also res people during combat.
Dark Templar - damage is not as good as the conq, but are able to self heal. Makes a good off tank and they are getting a HUGE buff in the patch
Ranger - Best pvp killer sub lvl 60. You are way overpowered below that lvl.
Barb - Great damage dealer, can lock down clothies.
Assasin - Like a barb but with less damage.
Hope this helps.
I have x4 80's mostly purpled out
If you roll a pvp server, stay out of White Sands unless you want to be killed at early levels. GL hav fun