I’ve been looking for this one for some time now. I know there are several tools out there that do the same but none of them are Freeware! Check out WinDirStat. It’s free and gives you a great overview of which folder contains the MB’s! This can be very useful on fileservers when your disks are magically filling up with all sorts of “garbage”. Especially the “extension lists” is very useful, at one of my previous employers we noticed about 25GB of mp3’s and a whole bunch of iso files on our fileserver which definitely should’t have been there! In other words, pick it up! This one is useful! (the source)