Do you want to know which files on your computer take up a ton of space? I do, frequently. Being the system administrator at work and at home trying to keep my Dropbox on a free plan, because to be honest, how many files do really need to have access to at any point in time?
Anyhow, the following programs make the information of what really takes up space on your Windows machine, Macbook, Linux hacker heaven box and what ever else you installed an operating system on very accessible. Analyzing your disk space visually is much more intuitive than trying to understand the raw numbers and compare them in your head.