New Quintboxer... deciding party

Hi. I've just made the plunge to quintbox wow. Four WoW battlechests will soon be on their way from Amazon ($30 ea, not bad), and I have already reffered-a-friend myself 4x so I now have 4x 10-day trials and my main account.

Now comes the hard part: What type of party do I want?

I want to stay on Arthas where my two 70s reside, and my main account only had room for 2-3 new characters (I hate deleting ones I've leveled past 20). So that sort of limits how many parties I can start. I come here for your advice on which ones work well and which ones don't.

Ones I was thinking of:

5x Elemental Shamans is an obvious choice. Tons of benefits to having them, including near fear immunity and the benefits of mass-confusion-causing-clutter via totems, rebirth, ooc res, great burst dps, etc.
5x Shadow Priests is one I have been mulling this one around. Fear ward would help with fear bombs, not to mention having virtually unlimited fear-bombs myself. Not many melees would be able to stay near me long. Mass-dispel so no bubbles or iceblocks would stop me, and perhaps the biggest benefit of all: 5x vampiric embrace/vampiric touch.

The math seems pretty impressive: Say with 800 +spell dmg, a single 3-second mindflay would do 1000 dmg, and with talents cost about 196 mana. With 5x SPs doing it, it would return 25% of it's damage in mana, or 250 mana! So essentially, once geared, the party will NEVER run out of mana. Additionally, they would heal eachother for 1250 health over 3 seconds (not a bad HoT). And that's all from 1 mindflay.
4x Warlocks, 1x Priest I'm drawn to this one because of ........................ <- yeah those are dots.


Anyway, can anyone who has tried any of these give me some tips?