**insert obligatory "just play the game, farming is degenerate" comment here**
Now that that's out of the way:
Well, it depends on what campaigns you have and where you've got access to.
Eye of the North Raptor farm uses the ele or sin.
UW farm usues sin; you can try the dervish build too.
If you have monk somewhere, you can solo 55 or 600/smite team. You can even use a hero for the smiter.
http://pvx.wikia.com/wiki/Category:G...farming_builds
That all said... capping skills often nearly pays for itself. Pick up every drop, ID it all, and you can often come out with 800 to 1k. More if you can do it in HM.
Is there a reason you're not rolling a PvP character? Do you need to unlock all the skills anyway, and that's why you're doing this? If I'm not mistaken, the needs for armor, health, energy, runes, and weps might be notably different.
Good luck.