Alright, if you want everything I suggest you get a steam account(free), and then with a credit card, or debit I think, buy Half-Life 2 Silver Package.
The silver package should get you every game on steam.(Download) You won't get the CD-Keys though(doesn't matter since when your register the key to your steam account you can't register it again) or the packaging.(CD's, Manual, Jewl Cases, Ect...)
Silver Package:
Half-Life
Half-Life: Deathmatch
Half-Life 2
Half-Life 2: Deathmatch
Half-Life: Source
Day of Defeat
Day of Defeat: Source
Counter-Strike
Counter-Strike: Source
Condition Zero
Condition Zero: Deleted Scenes
Codename Gordan(free with steam account | 2D)
Team Fortress Classic
Opposing Force
Riochet
Valve can't sell you BlueShift though.(I didn't like it much anyway) The silver package is around $ 60.00 USD.