Counter-Strike: Source, Day of Defeat: Source, and Half-Life 2: Deathmatch is $30
Half-Life 2 is $20
Half-Life: Source, Half-Life Deathmatch: Source is $10
CS 1.6 is $10
Team Fortress Classic, Opposing Force, Half-Life, Half-Life: Blue Shift is $15
So in total the account is worth about $85 just for the games on it.
Anything less then about $45 and I would be selling the account for half what its worth.
That account probably won't sell for more than $40 max... on average I'd expect it to go for around $20-$30. You have to remember, unless it's a low digit account, the account will remain a low price.
Becuase people can go and buy almost the same account with their own money and not have to worrie about hassles or scams, i would either wait to sell that account, or sell it cheap.