Originally Posted by Thrasher 
Check out this link to analyze your Steam library. It's best to have a SteamID set up.
Calculate your Steam hours-played, shameful backlog with this web utility
My stats:
Games Owned: 78
Games Played: 7
Games Never Played: 71
Percentage Played: 8.97%
Total Hours: 905.80
Interesting - wow I thought I had a bad backlog.
Games Owned: 139
Games Played: 47
Games Never Played: 92
Percentage Played: 33.81%
Total Hours: 1815.00