The advantages I agree with are in posts #9, #12, #13, #17 and #18.
I feel it makes storages easier and more organized and speeds up defragging when you don't have to defrag the entire drive. I just defrag the C-drive.
PS: Since I mainly use Ubuntu now there is NO need to defrag at all.
Windows requires routine defragging.
Linux requires NO defragging, it just runs worry free...
Well, it's not that Linux requires no defragging, it's just that linux filesystems put a lot more thought into writing things on the disk in the first place. Also, linux encourages the use of multiple partitions (There is no concept of drive letters, everything is just mounted into one filesystem which makes expansion easy).
If you are using Ubuntu you should look into setting up a software RAID array. I use Debian have two 1 TB SATA Disks. They are set up in a mirrored software RAID. (The Debian and Ubuntu installer will do this easily)
Disk 1: 1.5 GB SWAP | 50 GB '/' | 50 GB '/home' | 900 GB 'media'
Disk 2: 1.5 GB SWAP | 50 GB '/' | 50 GB '/home' | 900 GB 'media'
The SWAPS are never used, but if they were they'd be interleaved, plus suspend to disk uses SWAP, and the rest of the partitions are exact mirrors. That way if a drive fails, I just pull it and replace it, and re-sync the RAID. I also dump /home and the media partition to a USB Disk every couple of weeks. If you set user / group permissions on your media you can prevent deletion accidents.
Because of the flexibilty, and standard tools in linux software RAID is > hardware RAID, IMHO.
Once every couple of years I buy two new drives, and copy the stuff over. I could also buy two new drives, install them, mount them as a dedicated 'media' partition, then grow the '/home' partitions, but that would get loud and the USB disk would be too small for backups. (Historically one old drive gets used for backups and one is given away.)
As far as the Windows guy goes-- There are a number of 'free linuxes' that might let you grow or shrink a NTFS partition, plus there are some commercial tools that will do the same. Mind you always backup your stuff before you mess with your partitions. Stuff happens.