I've been playing World of Warcraft since Day 1 back in 2004 (when the game consisted of a few thousand, was poorly designed, and was relatively sane) and I can say that now, six years later, my desire to play it obsessedly for a long period of time is gone.
Sure Cataclysm just came out and its fun to play for a multitude of hours on end, but overall the luring effect isn't there anymore.
My best advice regarding WoW is to play it in a controlled fashion, and not get too carried away with the more grandiose aspects of the game (for the record, once your character is at max level there is no reason to go ape over every little stat or achievement when the main attraction should be raiding with 9-24 of your friends on select nights).