Bit dull this, perhaps, but mightily useful. Free application FosiX will allow you to visualize your hard disk space as a series of bar graphs or pie charts. You load it up, tell it where to scan, and it’ll show you some very pretty graphs, mostly likely highlighting exactly where your porn video stash is, so be careful of that one.
If you left-click on a bar, it’ll dig deeper and show the contents of that directory as its bars instead, and if you right-click then it’ll open that directory in internet explorer. I used to be a big fan of Sequoiaview to do this sort of thing, but I think I’ve been convered to FosiX, thanks to this left/right click functionality.
FosiX Lite is a free download, and can export into HTML, CSV and Excel. There’s a Pro edition with a ton of extra functionality that’ll cost you, but FosiX Lite does everything I’d ever want it to.