Is Ubuntu losing its crown to PCLinuxOS?

Quick. Name the most popular Linux distribution. You probably guessed Ubuntu, Suse or Mandriva ... but what then? Which other Linux distributions are likely to make a top ten list?

Inspired by a recent post on Datamation by Bruce Byfield (The 7 most influential Linux distributions), I took a new look at the various Linux distributions available and came up with some unexpected results.

The one problem is that there is no definitive way to decide precisely which distribution is the most popular and which others it beats out.