Hi guys,

I multibox with 4 locks and 1 priest.
On my locks, I use this spec:
7/44/11 - http://www.wowhead.com/?talent=IV0oZbxczIizzestxx0z
I've found this to be great spec for both PvE & PvP. It gives you felguard, which is a better tank than the voidwalker IMO, and very handy in PvP. You also get instant corruption, a reduced casting time on Shadowbolt and Soulfire, and an instant nuke - Shadowburn. Intercept (2 sec stun), followed by 4 x Shadowbolts (2 sec cast), and finished up with 4 x Shadowburns (instant) will drop a player in full T2 Arena gear.
On my priest, I use this spec:
18/43/0 - http://www.wowhead.com/?talent=bxThzhZfxtccMVVhVo
This build is designed to throw out the biggest heals with the least ammount of threat - especially since in intances you'll be healing your pets a LOT... CoH is fantastic when combined with the locks' Hellfire (both for PvE and PvP), and it's a great backup when the shit hits the fan (instant heal spam!). Note - in 2.3 CoH, Holy Nova & PW:S will get additional benefit from +spell dam/healing. Also Meditation moves to +10/20/30% mana regen in the next patch as well, which makes this talent definitely worth having.

Hope this helps...

Cheers,
Stealthy