Well, luckily, it seems that you can keep either the classic look or the newer, XP look as default. The GUI should be skinnable to developers.
This is a new feature included in Windows XP. "Based on the Windows 2000 profiles, user accounts are created for all users during installation. As the default, passwords are not required, although users can create them if desired. A friendly new welcome screen featuring user names and pictures or icons rather than code names or aliases replaces the logon dialog box. Further, a new control panel applet makes it easy to add and edit user accounts. Each user has their own settings, including wallpaper, music, pictures, favorites, and so forth. In fast user switching, multiple users do not have to not log off when using a single computer. Instead, their accounts are always logged on, and they can switch quickly between all open accounts."
The first developers preview was sent out to testers mid-July 2000.
Windows XP employs Windows 2000 power management features
Graphics Device Interface Plus (GDI+) is the portion of Microsoft Windows.NET that provides two-dimensional vector graphics, imaging, and typography. GDI+ improves on GDI (the graphics device interface included with earlier versions of Windows) by adding new features and by optimizing existing features.
64 bit compatibility
Support for high density displays