In addition to testing out the Windows XP Start menu on beginners, we asked advanced users (including lots of system administrators) what they thought of it, and the response was still positive. This was kind of surprising, for advanced users tend to be resistant to change.
In fact, system administrators like the new Start menu so much that they asked for a special "server administrators" version of the new Start menu. Explorer decides whether you get the "normal user" version or the "server administrator" version of the Start menu based on your account permissions at the time you log on for the first time.
If your account is a member of the Administrators group when you first log onto one of the Server editions of Windows Server 2003, then Explorer sets up your defaults to be more suitable for server administration. The default pin list contains server management utilities (I forget exactly which ones, but I think "Manage Your Server" is in there somewhere), Explorer defaults to Details mode, and showing the full path in the address bar. There may be some other minor changes; I forget exactly.