One of my guildmates now has 11 level 85 characters. That's quite a lot, I agree. So, who's he going to level to 90? He's selected a raiding main, so they get to go first, and I believe that's one of his two warriors. After that, I think he's taking either a paladin or a priest.
I have nowhere near that many 85s, but they still have to be prioritized. The leveling process seems to be on the slow side of normal, what with the enforced reliance on quests and my dislike of questing, so there will necessarily be characters that wait a long time to get to 90. My first is my shaman, my main for PvP, and for raiding for the time being. Next, I reckon my paladin. I'm excited about retribution for this season, and she's my second raider.
But who am I leaving behind? For now, I'm sorry to say, it's my mage. She was a fun 85, but I'm not that excited about her for Mists right now. Well, I say that, but it's more that I'm much more excited about my other characters: warlock, priest, hunter, all getting some cool new toys to play with, that do it for me more than mages.
How about you, though? Who are you leveling as quickly as possible, but also, who are you leaving behind?