With the release of Left 4 Dead just around the corner, now would be an excellent to to reacquaint yourself with some of the wonderful games Valve has released in the past. To help you in that endeavour, Valve has released the Valve Complete Pack on Steam, a compilation of everything they've released since the dawn of time. That includes Half-Life in all its many forms, Counter-Strike, Team Fortress 2 and Classic, Portal, and hell, they've even got Peggle Extreme in there for good measure.
So how much does all of that run? Only $US99, and before you pull out your calculators, keep in mind that the package also includes Left 4 Dead itself, so you're basically getting all of the other games for $US50 more. That's a savings of $US134.82. The only way it isn't a good deal is if you already own all the other games, and that's just crazy.
Valve Complete Pack [Steam - Thanks Tenshigure!]