right now im dualboxing DK + Holy paladin
(used to 5box DK+4ret before getting bored and raiding solo again)

having a LOT of fun in bg's atm using ISboxer repeater regions and jamba strobefollow
setup Grid to only show my 2 chars and clickcasting my heals

i usually end with the least deaths (between zero and no more than 5) and therefor getting the most HK's
the new 4.0 holy pally has quite a lot of insta healing with a /castsequence holy shock, word of glory
and 1second flash of lights are sweet were needed.

2 healers will mean more healingpower when zerged (i die when they manage to cc both of us at the same time) but also more management.

Good luck though, im sure you'll enjoy it