If going for a complete reformat, then create 3 partitions:
1 - install win2k on fat32
2 - install XP and make ntfs
3 - have a fat32 partition for shared stuff, eg my docs etc.
You cannot (easily) access NTFS partitions from FAT32 partitions.
No problem with dual booting on NTFS disks - but you can only dual boot #NT / 2K / XP as these are the only OS which can be on NTFS.
I hope that clarifies things a little.