I jumped in and did 5 right off the bat you learn a lot by doing this. I previously did 2, years ago.... I also used to multi in EQ back when innerspace was brand new...

1x Paladin = I love them as face roll tanks, I have a DK at 90 ready to go if needed...
3x Hunter = easy DPS can macro it with ease, went BM because I don't want to have to watch for lock and load because it would be random on toons... Can use mages, locks what ever.
1x Priest = Healer, could do any healer here I went priest to stay with blood elf theme.

I like steady state predictable DPS, not waiting for something to proc....

I would suggest starting from level 1 and by the time you get to level 25 your doing Video FX and will have all you macros setup. Level 1 - 25 a 5 man team can roll through so not much danger in death. I only died one time because I didn't know the boss encounter and stood right in the aoe... Plus I didn't have good healing setup, was just leeroying the paladin in. The instances at these levels are not to bad either. can use dungeon finder with your team and teleport to each instance.

Addons

2 must addons

Jamba = helps with team, quests selling and various other things.
Some kind of healing addon like healbot for use with VideoFX watch the youtube tutorials.

http://www.youtube.com/user/Multiboxology

http://www.youtube.com/user/MiRaiPresents


Watch all of these before starting