Halo 3 (Xbox 360, 2007)

The single player campaign is short if you just want to find out what happens, but is significantly lengthened with the addition of competitive co-op thrown in the mix. And if that wasn't enough, there are "skulls" that can be collected to increase the difficulty once you are playing with more than one person (up to 4 at one time) since there can only be so many bad guys on screen at once. While this adds length to the single player campaign, the multiplayer is where the meat of the action is. Once you get online with the XBOX live service, the possibilities are nearly endless. So pick this one up and actually get your monies worth for a change.