Pretty much what everyone's saying. Necro/Cleric.
Necromancer branch classes work well with zerks/pallys when doing dungeons, arena, etc. Necromancers just make it way easier to do things faster with all their debuffs. Plus, you can't go wrong with the Leech Buff. Gawd. But yeah, me and my ex lover used to duo every single dungeon together, it was just fast and easy seeing as my debuffs and his agro/damage on things just destroyed everything \o/.
Clerics on the other hand would definitely provide you more heals than a Necromancer's Leech Buff. Plus, their buffs are super helpful. Might have to worry about them taking agro, a little. But they are tanky (if equipped correctly), and if you die, they can rez you,etc while holding agro onto something without dying, which a Necromancer is squishy, and would just run/stand there and die.
It's really just up to what you decide you feel more confident with, and like better. ^-^