here's the plan chiefs;
find a friend's account / account you don't use or such.
take said account, and discontinue it.
When wotlk hits, recruit a friend, grab a free zeebrah mount, game time for both accounts, and then the exp buff.
Start leveling both accounts together, so you both get the exp buff, and if i understand it correctly when you both get to level 72, you can automatically level your main to 73. This would happen every two levels.
Thus, level much faster and beat all your friends to 80, then show off with two 80s and gank some kids with your level advantage!
Voila you're ahead of the game.