I suggest a summon/corpse explosion necro. They are not really gear dependant, and they can solo through hell, while sorcs and melee chars have this problem with immunities.
If your in a group, i would do a sorc; because youll get to a high enough lvl where you can do decent mfing by more or less leaching through the low levels. its really just what your comfortable with.
But yeah the summon necro i always like, skeles are tanks and have good killing power; and you get to just chill. Then when that gets borning, and you have enough mana, corpse explosion.