I installed SP2 Final yesterday. I had SP2 RC2 installed since it was released to the public. I hadn't encountered a single problem with RC2.
The enhancements of the WiFi support is awesome. Before SP2 I wasn't able to use WPA encryption, but now I can!! Yippee!! I love the popup blocker in IE, and I'm sure there are alot of other fixes that I'll just never have to worry about now.
Download it at: http://www.microsoft.com/downloads/details.aspx?FamilyID=049c9dbe-3b8e-4f30-8245-9e368d3cdb5a&DisplayLang=en