I just ran into a utility today that allows you to check your cluster allocation size, sector size, and a bunch of other useful infomration including the location of your Master File Table and how many sectors/clusters are free.
The command is:
fsutil fsinfo ntfsinfo C:
The fsutil command requires administrative priviledges so make sure you right click and run as administrator.
For more information on the fsutil command and other options check out as there are quite a few more interesting commands to check out information about your file system.
To get more specific into the fsinfo command we used to display the stats follow the links to
Looking through the pages I found another useful command for when you need to dismount a hdd and the GUI just isnt working or you dont have access to the eject utility
fsutil volume dismount C:
Seems like a pretty useful command, I'm surprised i hadn't used fsutil before
Edit: One final really cool use of fsutil is creating files of specified size
fsutil file createnew C:\File-100MB.txt 102400000
The above creates a file that is 100MB in size great for testing transfer times or any other useful application