Before my motherboard crapped out on me I was playing about four hours a day, except on days off... that was an on and off again time for me, so roughly 10 hours on those days. Got really good at balancing housework while playing, and the kids like to watch and/or help me play.
I go through phases- hours and hours per day- like at the moment when i should be revising/doing somthing very important, but then I seem to quench my little addiction and wont go on for weeks- then back to about 4-5 hours a day.
it started off with a simple 2 to 3 hours a week... then weeks went to days, three hours became six and from six to eight... eventually it got so out of hand i played for a day straight before i stopped completely... it was slowly stealing my soul... so i got rid of it
I recently removed my The Sims 2 game off of my computer so I could make room for WoW, but before I would play at least 2-3 hours, sometimes 5-7 if there was nothing I had to do otherwise. I really miss it now that I'm taking a break form WoW. :(
Yeah, when I play, I usually play 3 to 12 hours. Which is why I don't play unless I've got a totally free day. I keep my disc at my parent's place so I have to drive 20 minutes to start playing. Addiction control ftfw!