My $.02 but I won't do much beyond echo what Mercurio says. Much of what I have learned I gleaned from watching him. Two pallies are the way to go. I used a paladin and a DK but found it difficult to match up their abilities of like kind (i.e. taunts, consecrate and DND). It worked and the DK was fun but I just switched to my noob, 3500 GS, pally tank for my second and it's much better. I also agree that dual speccing tank 2 as a 3rd (or 4th) healer is the better way to go. Movement and position with just one, part time, melee dps is tiresome.

Healers, I'm still undecided. I use a disc priest (tank healing) and a holy priest (AoE healing), but my best geared healer is a resto shaman. I love shammy healing. I may got with holy x2 just for the synergy. One thing I have learned from 10 boxing is simpler is better.

I am using my boomkin for his buffs until Cata but I'll be replacing him with a second mage.

I may have 3 elemental shaman in my raid, but now I have just two.

Double warlocks are nice! I'm even tempted to make one affliction but they are both destruction now.

I don't agree with the hunter thing only because I can't make it work. Regardless of spec my hunter barely out dps's my tank and constantly does stupid things to wipe my raids. If I could make him work I would keep him but I can't.

Another opinion, paladin healers are kind of tough to box. If he is only spamming heals on the tank it could work but two priests or priest/shaman have worked much better for me (my 2nd tank was a healer).

Same with Shadow Priests for me. They bring Misery to a raid, in more ways than one . . . Low dps, mana troubles and no synergy with my group makeup.

I am a permanoob at 10 boxing but I've been plugging at it for a while. Let me know if I can help :/

P.S. Mercurio, did you post your setup somewhere? You mentioned that you might do it sometime but I haven't seen it.