To really find out which files are the biggest consumers of your hard drive space, with visual representations, choose SpaceMonger.
What really differentiates SpaceMonger with other freewares of its type is that SpaceMonger will display file sizes with graphical boxes. The bigger the files or folders, the bigger the box will be. The birds eye view of your entire hard disk are possible now with SpaceMonger. Just by looking at the interface, you will instantly know which files to delete / move in order to conserve hard disk space.
Some people love texts, some love pie charts and some love graphs to get an idea of something. If you prefer pie charts, you can check out my review on JDiskReport.
or you can proceed to download SpaceMonger here