My Metor/Fireball Sorc decimates crowds, with a little assistance from my merc, full games of hell cows = gg cows.
My Setup is as follows:
33 skills (after gear) in Firebolt,Fireball,Meteor,Mastery = 11k fireballs, 21k meteors (no fire gc's)
Merc is wearing Eth Stone Dusk (3802 def), Delirium in a bone visage, bonehew (shael +amn)
The delirium does the work as it's wide array of spells fire off nice and often, while the merc's holy freeze aura slows everything down a bit. While he is up front attracting monster attention I bury him in showers of meteors and fireballs for anything that might wander my direction. As for fire immunes he does a great job of taking them out and the bonehew with the amn in it provides him with 7% leech. I found 7% to be a pretty good number as he doesnt die often, if you didnt have armor equal to mine I might reccomend two amns for twice the leech. Screenies Follow:
Merc Stat Page
Delirium in a bone visage
Eth Stone
Delirium In Action
Note: delirium also WILL cause your merc to morph into a bone fetish from time to time if he gets hit, he's quite the conversation peice for people who haven't ever seen it before
Bone Fetish *This screenie was taken before I switched to holy freeze merc.
Anyways, i swear by my delirium whatever hordes of monsters you happen to be fighting they turn and fight whatever is closest to them it also causes champions and unique monsters to fight their minions rather than concentrating on you and your party.