I tried using xcopy in Vista for the first time recently and received this in the command window:
NOTE: Xcopy is now deprecated, please use Robocopy.
It appears xcopy.exe is still available for appcompat so that existing batch files aren’t broken on Vista, but it looks like we’re being encouraged to move to Robocopy (‘Robust File Copy for Windows’).
Robocopy has been around for a while, shipped in at least one or two resource kits like the Windows Server 2003 Resource Kit Tools.
The biggest benefit appears to be the ability to create full mirror duplicates of two file structures (including all subdirectories and files, if you want) without having to copy unnecessary files. Only files that are new or have been updated in the source location will be copied. Robocopy also enables you to preserve the file information, including date/time stamps, ACLs and more.
And if you’re a GUI person, Technet has a GUI for Robocopy here.