Thanks for the quick responses! I guess what I was looking for with my original question was something to the tune of:

"How do other people who run dual-classes play their characters?"

But your answer, Totem, basically confirmed it for me. If anyone else would like to add by posting about how they dual-box (Pally tanks, Priest heals; Rogue DPS, Hunter auto-attack; etc)... I'm sure both myself and other beginners would love to read it.