My "Brief" List:
1) Get all 12 toons up to a combination of 4,000 JP/VP and 4,000 Honor (assuming the conversions are the same as when Cata went live). If they do what they did for Dragonsoul, I see much much much Heroic grinding in my future :/
2) Buy Agility Heirloom gear for my future monk.
2) Finish maxing out Basic Cata reps.
3) Finish Cata zone quests on all 12 toons.
4) Get as many LFR loot as possible (for future transmogging).
5) Save up as much gold as possible.
6) Clean out bank space on all 12 toons.
7) Work on that Druid alt.
8) Continue the never-ending quest of getting Broodlord Lashlayer to drop the ****ing
Heartstriker. 37 weeks and still haven't seen it on my Horde Hunter, and soloing Razorgore just isn't fun to do for those that haven't gone through it.
9) Continue working on getting other Transmogging stuff. This never seems to end either given how many sets I've put together (up to 52 now).
10) Relearn how to play my toons after the MoP class changes go live prior to MoP.
11) Set up priorities on which classes to rush to 89 first. This will have to wait till they implement the MoP class changes in the patch shortly before MoP goes live. And you read right, I said level 89 because of this:
Brewfest Holiday Boss. It may be a fools quest, but if they're bumping Coren to 90, I want to get as many of my toons eligible for him as possible and hopefully get them epic 90 trinkets
as well as one or two of the new Tankards o' Terror for my future Monk. I was content with just trying to pick up a missing Brewfest Ram mount, but if they're going to put the carrot out there, might as well go for it.
Edit: Had to strike through the part about getting tankards as the datamined info so far doesn't have them anywhere, but does have the horseman's pumpkin sword.