Tom Clancy's Splinter Cell: Double Agent (PlayStation 3)
I like this game because you can't beat it by simply running around and wildly shooting at people. It requires quite a bit of tactical strategy and has a considerable degree of difficulty. What's also cool about it is that it's almost like a choose-your-own-adventure title. The storyline adapts to the different choices that the gamer makes.
Played this game on PlayStation 2, im sure it's better on the new PS3 console. You can play it over and over again because the storyline changes based on which side you choose. Will you side with the terrorist, or the goverment?