NTFS isn't great, and yes they're apparently working on WinFS, but tbh iafter reading bits about the development, i'm unsure how different it will be when compared to NTFS, what they seem to be playing around with are things that will affect searching and sorting.
Apple and Linux file systems don't need defragging (as often - but this is debatable still) is because of the way they write to the hard disk, they look for free contignious blocks, rather than the next free block and the one after this etc ending in writing data to multiple places on a hard drive (if the drive has been used a fair bit - deletions etc...).
Once a hard drive gets full though even Ext2/3 can't help but spread data about, this is the one time where defragging *might* help...