Hmm...
Sad to see ppl still talk of DOS...
U see XP is not a Bolt-On on a Dos Chassis Platform.
My experience tells me NTFS is much better (Using it for 3 years...).
As far as Dos access is concerned.. Ur Dos applications will still run on windows Command Prompt(When u r in XP).. and ur drives will be accessible, Completly transparent. But Dos Based Disk Utilities wont work...(as they need low level access).
Native Dos Cant work with NTFS.. That is Dos booted from a floppy.
But u dont need it as XP comes with a Rescue Prompt (Can be accessed from a XP boot CD).
So unless u use some older than my Granny Disk tool (why?) u dont have to worry about NTFS messing up ur Dos applications...