It's a tough choice, I love my PS3, and all the wonderful games on it, but I also love the PS2 because it has some classics that I love, including Sly Cooper and Shadow of the Colossus, but I'd have to say the PS3, because it has all 3 God of Wars, almost every game that the 360 has, including Fallout 3, plus there are still games being developed, so it's likely I'll get to see a PS3 Sly Cooper game.
Plus it plays all and any blue ray movies, lets me play my shows on it, and is all around a system that I abuse like I would on pay day to a crack whore...