I'm keeping XP for personal reasons. However, 7 will replace XP on an international level in due time. The great majority of business and personal users are still on XP, mostly because the hype concerning the issues with Vista were well deserved. But 7 is real quality and everyone will come to learn it the way most computer users have learned XP. Most agree that personal users and business will hold on to XP as long as they can before upgrading. But as far as features go, Windows Server 2008 looks and acts just like 7 but can work with XP. This is important because the same was for the last (and still mostly used) Windows Server 2003 was the norm for so long and it complimented XP the same way.
For my money, 7 is a solid precursor to what will become 'most' standard. Its not just eye candy. I don't see how a Mac user could ever call a Windows OS eye candy. Its designed for ease and functionality for the novice to the advanced user. It is everything Vista was meant to be.
I think if it were not for the ailing economy we would be seeing a much stronger decline of XP in exchange for a 7 upgrade. Concerning what Windows is meant to do, meant to be among the masses, 7 is a home run.
But of course I prefer Snow Leopard. Still, I have a Windows drive with XP mostly for programming and MS Office. Though if you have iWork '09 (as opposed to '08) and only need limited MS Office use, then that is compatible and you may not need Windows on your Mac. It all depends on what you need.