Liquifile
Using the Finder to browse your files is so last year. The latest addition to the third party add-ons that hope to replace the Finder in your heart (and on your Mac) is Liquifile. This program presents a fairly basis outline of your files, however, it also graphically represents the size of the files in a folder (but not the size of the folder itself) with grey 'bubbles.' Liquifile also has built in filtering to help making that file you're looking for a breeze.
A 30 day demo is available and the full version will cost you $9.90.
