I'm a die hard multiplayer gamer. Everything from Quake to UT, 1942 to BF2, there is absolutely no AI that can be as diverse and challenging as a real human player. If I do play a single player game, it's almost always puzzle or solution based rather than a pure shooter. When I first got here at Naughty Dog and they told me that they were working on a multiplayer version of Uncharted, I had my reservations about it. Usually a game company can make a good multiplayer OR a good single player game. The only game that has broken that mold (that I know of) is the Call of Duty series.
In my biased opinion, Naughty Dog is also creating a great fusion/hybrid of the two with Uncharted 2. I really think this will be the must-own game for the ps3. You can easily get away with renting Uncharted 1. It's short, it's great but seriously, how many times are you going to play through the same story? Uncharted 2 however, has serious replayability with the multiplayer version. I sneak into the game every day when they test multiplayer here at work and I can say that it's definitely a well thought out game.
All this talk about Game of the Year is a bit early I think but it will surely be well received. After playing around with the ps3 this past week, I can see where that system is in desperate need for some good proprietary games. I see no benefit of owning a ps3 over a 360 and with the cost of the ps3, it just seem ludicrous. Sony needs to re-think what they are doing with this console and what they are doing with the Blu Ray format. Sony will never capture the market at $30 a movie.. but that's another article altogether.