Currently using Ubuntu 10.04LTS on both desktop and laptop. I think Mint is currently the most popular or it was last time I looked on distro watch. There are a lot of bad reviews about Ubuntu from the linux users at the moment regarding the new Unity desktop which a lot of people don't like.
In the latest release you can still switch between unity and gnome but apparently on the next LTS it will be unity only. Looking how much Ubuntu has fell from grace lately I think they may have to re-think that one