hm, that's a pretty good idea bringing a shadow priest, i went into MC/ony with my group (pally, 3 ele shamans, holy priest) and had severe mana problems, on all my characters... even with BoW, JoW, and mana totems. My pally tank ran out of mana then i started getting aggro problems on my shammys. Pally wasnt taking enough damage = didnt get enough mana back. And so i wasnt able to keep my threat up, and the fight ended up lasting for a while. And this was just with the first giant pack!! =P

Ill try going back in once i get a good spell-damage set on my paladin. But i may try speccing one of my shamans to resto, and speccing my priest to shadow, and see how that goes! VT could go a long way!