WinDirStat is a disk usage viewer that graphically displays your disk usage.
Very useful if you want to maintain disk space.
You can use the windows right click menu option "send to" to see the disk usage of any folder you want. Just place the windirstat shortcut in your "send to" folder (default location %username%\SendTo ). Now if you right click on any folder you can use sendTo option to check the disk usage of that folder.
You can download here