I went 68-80 in one day. With the RAF and the recent xp nerf, I blew through 68-80. I ended up picking and choosing which quests to do (focused on avoiding collection quests) and mainly spent my time in Borean Tundra, Zul'Drak, and Sholazar Basin. PvP in WotLK isn't all that much fun since the Blood DKs are just EVERYWHERE, but it's certainly better than the 55-59 and 60-64 brackets. I ran quite a few AV's since that neutralized their sting a little bit.