With my last round of RAF, I put in order the classes I thought I'd want to multibox at some point and then I leveled them to 60 until I couldn't handle anymore. In the end, I didn't make hunters, rogues, or warriors (or DKs, but those are easy to get to 60).

As I'm getting to 80, I noticed one thing - the classes I enjoy playing the most are ranged DPS with healing ability: priests, druids, and shaman. I'm sure locks and mages are fun, but in the end I personally loved being able to heal my toons with ease.

Just my .02 without a point :P