About 25% of Debian users who submit to the Debian Popularity Contest have VLC installed on their computer : http://qa.debian.org/popcon-graph.php?packages=vlc&

About 25% of Debian users who submit to the Debian Popularity Contest have VLC installed on their computer : http://qa.debian.org/popcon-graph.php?packages=vlc&show_installed=on&show_old=on&want_percent=on&want_legend=on&want_ticks=on&from_date=&to_date=&hlght_date=&date_fmt=%25Y-%25m&beenhere=1 http://qa.debian.org/popcon-graph.php?packages=vlc&show_... - that includes servers, so the actual proportion of Debian desktop users with VLC is much higher.