Are you leveling a new character once December 7th rolls around? Take stock of your heirloom gear. Log through all of your alts - yes, ALL of them - and see what they've got. Mail it all to one central character (I use a bank mule for this) and then redistribute it as needed.
Take into account how often you actually play said alts, if you're ever going to level or twink them...and if need be, delete accordingly. I went from 50 characters (the account-wide cap) to 26. Every toon I tossed was under level 30 and a duplicate of something I already had above 70.
Take stock of your higher-level characters too! Will the Cataclysm recipes make maxing their professions easier? Then you don't need to worry about getting up to 450 before then - save your gold and use it on something else.
Do you know what toon you're leveling to 85 first? If not, or if you want to level several concurrently (hi, I'm an altoholic) make sure they have what they need to make the questing and instancing process as quick as possible. Stock repair money, convenient buff food, elixirs or flasks (hey, we get new ones anyway), and anything else you consider a necessity. In my case, it's pygmy oil by the stack and cooked deviate fish.
Got a bucket list? Double-check it and make sure you're satisfied with your progress.
How are you on gold? Do you have stockpiled crafting mats sitting around that you won't use up in the next three weeks? Sell some now, or hold onto them until after Cata and sell them when people leveling worgen and goblins start powerleveling professions.
Last and most important - how are you doing? Are you interested in playing until we get new content? If not, consider taking a couple weeks off. Volunteer at your local pet shelter and hug kittens or walk dogs. Learn the basics of a new language. Walk a mile every day (climate permitting). Or pick up blogging... :)