WordPress is the most popular CMS out there. It powers a good number of websites and blogs, and owing to its popularity, the number of extensions and themes that are available for WordPress surpasses those of any other CMS by a mile.
Speaking of WordPress themes, the market is filled with options. You have free themes, premium themes, themes created by design agencies, themes created by casual designers just to kill time, themes created with passion and, sadly, themes containing spam and shady links. However you look at it, I guess the point is clear: