Tech: The Killer App
The PlayStation 3 is the only major video game console I haven't picked up yet, but that may change because of a little game called "Metal Gear Solid 4":
It's the PS3's killer app, a title that is not only highly anticipated but also exclusive to the system (unlike, say, GTA IV, which is readily available for the Xbox 360). I'm only a casual Metal Gear Solid fan (I've always thought the gameplay, while great, was chopped up by too many in-game cutscenes) but even I can't deny the appeal of Solid Snake's final mission.
Only problem is that, aside from MGS4, there really aren't many games to look forward to on the PS3. The heavy hitters, like Final Fantasy XIII, God of War 3, and Gran Turismo 5, aren't due until 2009 at the earliest...with a chance of being delayed till 2010. That's a long time to survive on just the exploits of Solid Snake.