I just bought the Valve Complete Pack on Steam a week ago, and what a purchase it was! It contains all Half-Life, Portal, Counter-Strike, Left4Dead and Day of Defeat games, with other single titles as Team Fortress Classic, Ricochet and Deathmatch Classic, with an insane -91% discount in cost, from 120€ to only 11€! Thats an insane discount, with the greatest games of all time!
Note that Im not sententious that I bought it, I just want to show off how awesome this package really is! :P