Installed XP SP2 on about six machines now. It's working fine on all of 'em. Only app it complains about is Trillian, and it's just a matter of checking the warning-box saying "yeah, it's okay to let this app run. I trust it."
In any case, I'm sure people are gonna complain up a storm about how it's incompatible with
It even congratulated me for being connected through a wireless router that encrypted the broadcasts and didn't allow random connections :)