i installed SP2 last week and it has been nothing short of a nightmare for me. there are problems with application stability, the firewall acts weird if you already have a norton or symantec installed, there are problems with executing java programs, problems with running multiple instances with various applications, errors when attempting to build from eclipse, etc. etc.
the list goes on and on.
if any of you work in large companies and your sys admin has downloaded SP2 for you to install, do not install. it is a headache. and it is a female dog to roll back, even if an image is saved.