Windows still does not include a simple utility that will show you where the largest files on your system are located.
Why this is the case I have no idea because large hidden files are one of the most annoying problems in Windows, taking up valuable disk space but serving no useful purpose. Free Disk Usage Analyzer is a very useful tool which helps you organize your files and manage disk space by locating the largest files on your disk. You can quickly find where are your largest files, such as videos, photos and archives, and move them elsewhere, such as to a backup drive.
Of course, if the files are no longer useful, you can just delete them. One such example could be video files that have been cached by sites such as YouTube or Google Video that you no longer need. Scanning may take a while depending on how large your hard drive is but results are displayed in real time as it collates them. Free Disk Usage Analyzer also allows you to view the files by type in a convenient pie chart format.
It would be useful if you could preview what each file contains before deleting it but as a simple search and destroy tool, Free Disk Usage Analyzer does the job.