If your not afraid to use terminal, issue this command from your home directory or whereever you want to start.
ls -lRS | more
The l's are both lower case L's not a 1.
This comand will list all files in all directories. Within each directory the files will be sorted in descending order by file size. The space bar will go forward one screen. The letter b will go back one screen. q will quit.
If you do
ls -lRS > myfiles.txt
It will create a file you can look at with textedit.
It is a lot to look through but really big files will stand out.