I just bought Valve’s The Orange Box: 
It’s only $40 for FIVE (great) Steam Games.
Half-Life 2
HL2 Episode One
HL2 Episode Two
Team Fortress 2
Portal
I already have HL2 but the other four are new, I have played the Portal Demo though (First Slice) and really enjoyed it. Team Fortress 2 looks pretty good too, I have the Classic version of that already. The cool thing about already HL2 is the fact that Valve allows you to pass your extra copy to a friend if you want. =D Neat.