I purchased both on day one. Uncharted 2 was one of the greatest gaming experiences I've ever had. MW2 is a lot of fun but I do feel as though I've played the same game twice in the past two years.
I've always had a preference for games with strong storytelling. And in that regard Uncharted 2 has few (if any) peers. Personally I'd give it game of this generation and I'm not even sure it'd be a close battle.