[If there is only one 10.6 review/recap you read, it should be this one][link]. John is the best at this. It is part history lesson, part analysis, part commentary.
[link]: http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars “Mac OS X 10.6 Snow Leopard: the Ars Technica review – Ars Technica”