I have both xp and Windows 2000 Advanced server installed on the same machine. I have setup a dual boot, but I had Windows 2000 Prof and Windows 2000 Prof with a dual boot before I put XP on the machine. I update Windows 2000 Prof with XP and almost everything work OK.
I am going to try to replace Windows Advanced server with professional this week end. I am a developer and need various environments to test.
There are several device drivers that work on W2K Prof that do not work on W2K server.
I use Partition Magic by PowerQuest, I had to buy an update to work with XP, but it seems to work fine.