Valve: The Complete Pack includes three CounterStrike games, ten Half-Life games, Portal, Team Fortress 2 and the Day of Defeat series, as well as several other titles.
Valve says the price for all these seperate items together would be nearing $235, though you’d have to be a multiplayer lunatic to want to buy all the deathmatch games on offer.
The full list of games available can be found here.