Ok... so after playing around with Vista for a couple days, I did finally find a NEW feature -- actual useable functionality not present in XP!
The Vista Disk Manager can resize partitions without data loss. It does have an odd limitation that it will only shrink to 50% of the current partition size regardless of how much free space is available. It also won't move unmoveable files like the MFT.
Running Partition Magic / gparted on XP would allow you to resize much smaller since they don't have the artificial 50% limit and they will compact/defragment the drive including those "unmoveable" system files. However, just having the ability to resize your partitions is a welcome addition to the default Disk Manager even if the feature is less powerful than some of the much older commercial and free software out there.
This means for the most part you won't need Partition Magic which doesn't seem to work with Vista anyhow or gparted which only works with some voodoo requiring a Vista Installation Disc -- not a "Restore" Disc like Gateway gave me :-(