XP *shudder* nice looking interface with added lack of privacy, added incompatibility, added money to microslugs and many more features. Ok so it's supposed to be more stable. Well it was about time for something stable to emerge but that doesn't really matter if you don't feel like visiting their web site and get counted among the sheep or if your computer is compromised, that sort of makes it more incompatible.
BTW I was wondering about antivirus? On a 98 machine you can use a dos boot disk with the scanner on it to scan and remove viruses from a deeply infected machine. What do you do if your XP gets infected? I doubt if you're running NTFS that it'd be a good idea to run a DOS program running one of the FAT systems through that harddisk.
As for winUAE. It's still a great emulator. It runs a darn lot, but unfortunately for me I can't use it at full speed which is one of the reasons I prefer to use Winfellow when I can.