Keep in mind, too, there is always re-specing and dual-specing. No reason to try to level as a tank and healer out on your own when you can use a tank+healer for dungeons and run in secondary spec as 2 DPS, or 1 DPS and the other as tank or healer for "tough" kills.

Especially if you can run classes that can use leveling gear as double-duty, such as ret/prot pala, ele/resto shaman, balance/resto druid or bear/cat druid....and so on.