best NT-based OS?

What do you think is the best NT-based OS? From NT 1.0 to all the to Windows Vista, what do you think is the best NT-based OS?
Mine is prolly XP, or 2000.
and state why!

 

Windows 2003

Simple straight forward UI, Shadow copy, remote administration. The more I use it, the more I like it. It just gets on with the job of supporting the applications that run on it. For me it is the unsung hero of Microsoft operating systems. If you could assign permissions based on OU membership, I'd be as happy as a pig in ....

On the desktop 2000 pro is great, but the addition of remote desktop just gives XP Pro the edge.

NT4 could be difficult to set up initially, but once it was configured it worked well for me. When plug-and-play starts playing up, I sometime wish for the days of NT4 when pnp was just another new kid on the block and could often be over-ridden with manual settings.