With best gear in the game you're going to have all the melee classes ahead of the magic classes. Paladins/Shadowknights with a 51/53 2hb + max str & max haste, or a 39/47 with 200+dmg ice proc will put out higher numbers then any caster. The reason being, a casters spells are as effective now as they will ever be. Necros/mages can slightly boost their overall maximum DPS by getting focus items, but that's it.
I pick paladins/sks to talk about simply because they're without a doubt the lowest DPS providing melee in the game (i don't count bards as melee)
(gear references)
http://wiki.project1999.org/index.php/Blackstone_Maul
http://wiki.project1999.org/index.php/Frozen_Zweihander