Shoved SP3 on my system a few days ago - can't see any major changes though!!
In my opinion SP3 is just a wrap together of all the major fixes from SP1 and 2. Not much else though. If someone notices anything else that it's doing tell me. I follow linux mainly and not as much windows.
I wouldnt know...I'm not on XP

no just allows the cia to hack into your computer better....

>_> If the CIA was hacking my computer, I'd be scared...
It's not that I do anything illegal, it's just a bit creepy, people spying on me.