du -xakm /|sort -rn|head -500 > bigfiles.txt

This saves (quickly!) a list of the 500 biggest files on your Linux / Unix / Mac OSX system, along with their size in megabytes, and organizes them with the largest at the top. Cool!

It’s saving me this evening - thanks go out to a commenter named georges at http://www.cyberciti.biz/faq/find-large-files-linux/