Bill McCarthy has an entry on a possible bug he has run into since upgrading to SP2. Take a look. It's pretty minor, but if you know about it before it happens, you won't waste any time trying to figure out the workaround...
I haven't installed SP2 just yet. I'm waiting to see if I hear about any showstoppers. So far most of the reports are pretty positive, unless you're on Slashdot, in which case any discussion of SP2 is responded to with 'suggestions' to upgrade to Linux!