Information Week have published a very detailed look at what changes with Sp2; well worth a read. Find out exactly how that $300 million has been spent.
"Remember when Microsoft said service packs wouldn"t deliver any new functionality? That lasted for about six months back in 1997. Windows XP Service Pack 2 is jammed-packed with both invisible and visible improvements to Windows XP. The biggest boon is that the free update, which will probably ship some time in September, does in fact make Windows XP far more secure. Many of the other user interface bits are aimed more at protecting Microsoft, you, me, and everyone from what consumers don"t know about securing their computers. As a result, they just don"t matter that much to IT shops.
But Microsoft isn"t wrong on that point: Many home and casual users really aren"t paying close enough attention to security. And when blended-threat household-name viruses and worms start using multiple means of spreading themselves around the planet, the fact that several million consumer boxes have been plugged up (as soon as SP2 ships!) is a very good thing indeed.
Nevertheless, just how much might all that consumer touchie-feelie stuff get in the way? I"m going to explore all major aspects of the service pack in a multiple-part series on Windows XP SP2, based on the recently released RC2 code."