As a result of a busy work schedule, my Shaman have been receiving little attention, other than quick 20-30 minutes breaks. But she is creeping closer to 80.
My aim is to have all my characters at max level by the time Cataclysm hits. So on the to do list: Hunter - 70, Warrior - 70, and Mage - 51.
The heirloom items are amazing for people like me that love to play alts. +20% XP allows you to breeze through the levels. In a good gaming session of 2-3 hours you can easily knock out 1 level (with restedbonus XP).
My AH "game-within-a-game" is keeping the gold flowing on a steady basis. My buy-cheap gear, disenchant and sell enchanting materials, nets me 100+g per day for 5-10minutes of effort. Its enough to pay the cost of leveling and buying gear for future use/end-game, as well as the mounts/riding skills.