I honestly base all of my purchases off of how much length and replayability I'll get out of a game, hence why I play mostly rpg's. For a game like skyrim or world of warcraft, I consider them to be the greatest games of all-time because they are the 2 longest games of all-time pretty much
For games like Portal 2 and Dishonored, even though they may be "good" games, I consider them utterly offensive and downright horrid because of how short they are. Seriously, Portal 2 being a 3 hour game is a slap in the face.
I've already put 1400 hours across 5 playthroughs on Skyrim, and easily 20k hours on world of warcraft since 2006.
I'm hoping for some more long games this year and for the ps4. I sure do crave long things.
this screenshot is for warcraft 3 players: http://img10.imageshack.us/img10/5835/masscritters.jpg