There are some severely fantastic games on ps3 for anyone on the fence about getting one.
Uncharted 1 & 2 --- uncharted reminds me of how great tomb raider was when it first came along only it is exceptionally better, = both perfect 10's.
Infamous --- like prototype but far better & doesn't seem repetitive & isn't a rushed production, you can just tell it was made with a passion for making an awesome game, great graphics, awesome animation, top notch gameplay = perfect 10.
Heavy rain --- it actually has better graphics than any pc game I played & I've played crysis on max settings @ 1920x1200 lol, some points in the game look incredible & I could barely beleive it was running on my ps3, the faces, animation, the rain, never seen rain look so good in a game, best usage of six axis I have experienced so far, example: putting a lit match out was surprisingly like how you would in reality, this game is special on so many levels and totally deserves some awards for being different and pulling it off so awesome, in a way it is like movies reinvented, I give it a perfect 10

.
For those games alone I would say it is worth having a ps3, of course there are many others worth getting depending on your taste but the ones I mention are my personal favourites and definate keepers that will keep me coming back for more.
I also have an xbox 360 but never gets used and not even sure if alan wake could change that lol.