As a latecomer to PS3, I've played the best games on PC for the last 14 years or so. After my recent switch to playing consoles again, I can confidently say that Uncharted 2 is the best game I've ever played. The graphics, dialogue, characters, set pieces etc... it's all perfect.
As in the first game (I've not played the 3rd game yet), I cared about the characters, as they were charming, witty and realistic. I empathised with them and cheered after they survived every scary encounter.
It took me 18 hours to complete on normal setting (I'm not a treasure hunter... only stumbled across 32 of them) and I found the length to be just right. After the first game, this sequel really shows all the other developer's how it's done. Also, buy this game just to see the best digitial bum on any format... Chloe's behind is perfection personified ;)
As stated, the graphics are amazing... I'd say they look as good as the best PC games of 5 years ago (the time when the console was released of course). But the graphics on PC games were actually really good even 7-8 years ago, so these PS3 graphics still look awesome to me today, and I'm a PC snob who usually sneers at console graphics. This looked and sounded out of this world on my 42" TV.
Overall, a 10/10 game.