Oddly enough, monks and bruisers top the charts for highest magical hit across the board, followed by a few guardians/bezerkers/assassins.
Down around number 20-25 on any top 100 list you'll start to see Wizards. Warlocks don't show up on the chart until around number 40.
If it's between Wizards and Warlocks, Wizards hit for higher burst damage, but Warlocks right now can do much more damage than Wizards in a long multiple mob encounter. This is because of better power consumption rates and because Warlocks have more of a AOE/DOT method of nuking, whereas Wizards have more of a Direct Damage, single target approach.
Wizard's lvl 50 Direct Damage Nuke, Ice Comet, does upwards of 3500 damage (I think).
Warlock's last Direct Damage nuke is lvl 37 Nil Distortion, which only rarely hits above 2000 damage.