I know this is kind of an odd question and sounds like it belongs on the WoW forums, but I'd like to take advantage of all of your vast experience, as I think only multiboxers can truly answer this question well.

Unlike the general forums, where the average casual player has maybe 2 80s max, and even the extreme hard-cores probably focus on 3 to 4 (my guess), multiboxers have the good fortune of being able to sustain 5 to 9 unique classes at 80. (especially those running mixed teams). And unlike a casual who may focus on one, MBoxers focus on ALL, tweaking macros for max DPS, etc.

If something forced you to stop MBoxing and choose only ONE class....which would it be, and why?
Please include the number of unique 80s you've run, and how far (Normals/Heroics/Raid/etc).