Have dome the SP2 upgrade on my box. Not much to say really. Doom3 still works, which I guess is the main thing
The firewall is a bit crappy so I'm still using Kerio which is better IMO. However, SP2 doesn't recognise it so keep asking me if I want to "correct the problem" and turn on the XP SP2 firewall. On the bright side SP2 does recognise AVG Anti-virus so doesn't warn me about having no virus protection.
Not looked at the IE changes as I use Firefox so they've not very intersting to me.