Tracking down where disk space has gone on Linux

When administering Linux systems I often find myself struggling to track down the culprit after a partition goes full. Here's a solution which relies on standard Linux commands to find where all that disk space is being consumed.

du -h / | grep '[0-9\.]\+G'

One caveat: Don't go straight to du /. Use df to find the partition that's hurting you, and then try du commands.