I would say Fire, Dark, Electric, and Ice because they all have an AoE damage aura. Out of those 4, I would choose Ice. It can take the alpha the best out of those 4. It will have the highest mitigation with a full group. Then the -ToHit from DM will pair nicely with the defense of Ice. Ice also has -rchg resistance, so you won't slow down hitting siphon life and most of all killing, although you won't be getting hit much anyhow with soft capped defense and -tohit, but those pesky Psionic hitting NPCs which slow recharge won't affect you much.