Prosoft Engineering has updated Drive Genius
(http://prosofteng.com/newdesign/products/drive_genius.php) to
version 2.1, which adds a DriveSlim feature. This feature allows you
to scan your hard drives for files that you may want to delete,
“which will free up valuable hard drive space,” says Greg Brewer, CEO
of Prosoft Engineering.

Drive Genius 2 is a disk utility with features that allow you to
maintain your hard drives. It offers disk defrag, directory repair,
repartition on-the-fly and more.

Drive Genius 2 costs US$99 for a personal use license. Updates to
version 2.1 are free for registered users of version 2.0.