dezinedepot

Ok, so the final five from the packt publishing contest were announced in September. Listed here in alphabetical order:
Drupal, e107, Joomla!, Plone, Xoops

I couldn't help but noticed that they are all based on php except for plone which is based mainly on python. Popularity wins the day! :)

For those that like more data than you know what to do with here is the trend according to search on google
drupal    e107    joomla    plone    xoops   

This shows Joomla with a monster lead in popularity in terms of search.