I forgo a fair amount of sleep to play. I was staying up until 2-3am and only getting 3 hours sleep to play.
My average play time for the first 4 week since expansion launch was ~6 hours per day. This is on top of working 50 hours per week.
I've eased back now. My schedule is roughly:
Mon: 8pm-11pm (raid)
Tues: 10pm-11pm
Wed: 8pm-12 midnight (raid)
Thurs: 8pm-12 midnight (raid)
Fri: 8pm-2am (if I don't have stuff on)
Sat:7am-11am
Sun:7am-11am