WoW is too good, stay away. Instead of thinking about my future during my first two years of UG I just wanted to play WoW all the time. I kept good grades, but I seriously didn't go more than 20 seconds without thinking about that game. I quit in the summer of '07 and have managed to stay away since, although it's been VERY hard. You can't play for 3 years without becoming close to the people you play with, albeit being complete strangers you will never see in person; although the loot was fake, the good times were real. I still visit the WoW news sites frequently and read my old realm's forums once in a while, but I've stayed out of contact with all the people I played with. The first month after I quit was the absolute worst, I returned to my dorm at around 10:00 every night after studying, and sat down at my laptop ready to fire up WoW until 2:00AM before I remembered I uninstalled it a few days prior. At which point I sat at my computer desk staring blankly into the screen for the next half hour, thinking "What now?".
My recommendation if you want to play is don't join a guild. It'll be easier to give yourself breaks if you don't have any emotional investment to other people in the game.
On the positive side, many of my mnemonic for classes are based on abbreviations and other things I got from WoW: AV, RFD, BG, and BRD come to mind
