I'm on the computer on average 5 out of the 8 hrs I am at work - doing setup and design work, plus I am the IT dept, so some days its more like 9 hrs.....
Then I usually spend 2-5 hrs at home each evening on the computer. So on your average weekday I usually spend 7 to 10 hrs on the computer, then some time on the weekend - anywhere from just a few hours in the evening to all day.