XP and W98se coexists well together.
XP and W2k is a different story. A lot of persons cannot get these two to work together. Some do get these to run side by side. I have not tried XP and W2k, the most dual boot systems I have are Linux and Windows. Linux and W2k does not ride very smooth together. Linux does not like NTFS at all. If you have the drive formatted fat32 everything seems OK.
I feel that if you run W2k, NTFS is part of the OS. The OS is very stable when using NTFS, but not so much when installed over Fat32.
This has been my expierence.