I refuse to upgrade my Windows 2000 boxes (Server and Pro) to Windows eXPerience. I simply can not find any significant technical reason for an upgrade at this time, especially considering the costs and lost time involved in the migration process.
As to interface concerns, I use custom shells like Aston and SharpE, so there are no concerns from my perspective.
For a person deploying a new installation of Windows, then WinXP is certainly satisfactory, though product activation is still quite annoying IMHO.
Robert Richmond