A dk and what else?

This has been driving me, I need some opinions here. Before we start, the dk is already 80 with some uld tanking gear (full pvp gear as well). It would be set up as a 5 box, with low experence with multiboxing.

What I have been cerious is what a good combo would be, the DK (boosting as well as when other toons hit 80 to still use the dk in the party) and put 4 priests, or 4 druids, or 4 pallys as the other ones. My main drive is pvp. Bgs and quite possably to do arenas (4 boxing with someone else healing of course). But allow there to be an option to do some raids like a 25 man naxx here and there when they need back up dps. Otherwise the only other PvE I'd do is leveling and dailys.

(3 shadow, 1 dc or holy)The priests would have some nice heals. But (imo), they don't do enough damage in shadow to make them roflstompers (I might be mistaken. It's that I've never really seem many shadow dpsers top the bg charts or the raid charts for dps.). Although the fear bombs, plus the buff is nice. But most of all that attracts me to priests is their bubble. I about jizz in my pants or curse at the world. Were I either get it, or have to take it off the other priest in 2v2s. (damn 1k res dc priests!)

(3 boom kins, and 1 resto)The druids would be awsome healers in pvp, as well as (imo) a bit better dps in boomkin then shadow priests.

(3 ret, 1 holy) The pallys would match up with the charge in tactic (run and and slap some silly horde / alliance around) I use with my dk (single box). Seems something that would be better cordinated. They are good in PvP, do good damage. RRing the mace stuns would be some really funny one sided world pvp or bg matches. But the heals arn't very friendly for muti-targets. But in pvp maybe rolling a few to ret/prot for that sexy sacred shield. Buffs from pallys are nice as well.

Any good ideas I stated? I'd like to get some of my opinions critisised. The basic 5 shammy box seems over used. Although wouldn't mind subbing something in for that sexy treamer totem. Other then that, I personaly wouldn't see putting any other class in with a dk to 5 box. Otherwise I'd love to see 4 of the same class for something more simple. Rotations and macros for a group thats all different seems like a pain in the ass.

For Arena.. generally, the best teams have shammies.

Most of them, someone plays four toons, and someone else plays a dedicated healer.
From what I've seen, Resto Druids, Disc Priests and Holy Pallies make the best healers.

For battleground play or world pvp, you can do whatever.

If you're playing them all, it will be hard.
The more toon types you control the harder it is.
You'd have 1x Healer type, 1x DK type, and 3x another type.
You can macro them down to a castsequence for PvE dps, and that's ok for PvP too.
But to be effective you'll want to be able to react, not just click the next thing in the sequence.
I'm not saying you cannot do it, just that I wouldn't expect a high rating.

Maybe the best would be 3 more DK's yourself, and have a friend play a dedicated healer.

Generally shammies are good in arena when boxed.... because...
They have massive controlled burst compared to anything else.
They have Grounding Totems to largely weaken caster teams.
They can purge a lot of useful buffs from others.
Heroism is a huge edge.
Tremor is probably the strongest Anti Fear mechanism.
Thunderstorm, Fire Nova and Earthbind are strong control options.
They are very well armored (good vs melee) for a caster toon.
They can support heal when necessary.

4 dks with a dedicated healer dosn't sound to bad. Although I'd like to make a char other then a dk, if it was pure arenas it dosn't sound like a bad idea. 4 frost speced dks with death chill and howling blast in full pvp gear would be enough to at least cripple if not kill the focus target and severly damage the ones around him. But the 4 shammys with lava burst looks like the best single target killer. It seems like 4 of them stacked is a 1 hit kill. But how would 4 dks fare vrs most of the comp? I'am sure that it'd be easy to CC. Although lichborn might help a bit, it still dosn't get rid of poly, freezing stuff, ect.

It all depends on your goals.

If you'll primarily be in battlegrounds, just about anything will work and be strong boxed. Fear bombs are your primary threat in battlegrounds. Fear Ward, Trinkets, Tremor Totems, Berserker Rage, there are counters to fear. You can also destroy anyone who you notice running towards you. They will hit fear on you now and then, nothing you can do about it, but its not the end of the world. With "Click to Move" and "Interact With Target", you can have all your toons running back to a central point with ease, so the fear is inconvenient but not the end of a fight.

For BG's, 4x Druids (Balance) is very strong. You could run the DK in a blood spec for decent damage and heals. When necessary the druids can 4x HoT's. They have good damage, Wrath, Moonfire, Insect Swarm, Starfire, Starfall, Roots on round robin, Force of Nature, Hurricane, Cyclone etc. The DK wouldn't want to be tank spec, since you cannot force someone to attack a tank. Four pallies with Click to Move/Interact would be a force as well.

Arena requires a lot more coordination and your composition becomes quite important. Boxed, pretty much the only teams that have been very successful seem to be 4x Elemental Shaman, plus 1x Healer (played by someone else). There are people who 5x Shaman themselves, but they don't seem to be as successful, although I remember reading of a Gladiator team a couple seasons back. Other compositions I'm not sure of, at the high end, at least when boxed.