5. The Orange Box (Half-Life 2, Portal, Team Fortress 2)
Team Fortress 2, Half-life 2 with Episodes One and Two, and Portal. Is there a better baseline of games you could have on a games console? Half-life 2 is one of the best first-person shooters ever created, Portal's charms are timeless, and Team Fortress 2 remains the third most-played online shooter on the PC. Sure, the Orange Box was available on last-gen consoles, but the TF2 community there is all but dead, and the technical limitations of the PS3 and Xbox 360 meant you couldn't play the games with crispy full HD (or above) resolutions, anti-aliasing, or every other technical perk you'd get on a Steam Machine. The Orange Box is a seminal piece of video game history, and its contents should be played ritualistically at least once a year so anyone unacquainted can appreciate the works that helped the industry get to where it is today.