As the titles mentions here's a little one liner when you want to find out who's are the top disk space users under a certain directory:
du -sk * | sort -nr | cut -f2 | head -5 | xargs du -sh
The command above show the top 5 offenders in a nice readable way (i.e not in kb which i find hard to read):
$ du -sk * | sort -nr | cut -f2 | head -5 | xargs du -sh 3.2G Offender1 1.8G Offender2 1.3G Offender3 1.1G Offender4 603M Offender5