60 - 70 just ran through outlands picking any non collection quests (unless the reward at the end was worth it).
hit 70 50% through netherstorm.

70-80 pretty much every Nortrend quest going (because the way quests are structured some only open up once others are done - just make sure you have all the gathering professions on your toons to clean the area). I made sure i got both the quest and exploration achievement before moving on to the next zone. (also did both Borean Tundra and Howling Fjord) before moving on to Dragonblight, then Grizzly Hills. i skipped Zul Drak. moved on to Sholazar basin(quested there till 79 then moved to Icecrown to start the Sons of Hodir rep). Dinged 80 in Icecrown 50% through the quests.

have now gone back and finished Sholazar, and am in the process of doing the same in icecrown, and probably Zul Drak as well just for the cash.