Open source CMS

Stunning.

The few that inspire awe. It's time for you to join their ranks and make online reputation.

It's time to stun your audience.

Which is best?

It depends on what you want to use it for. Thereís no magic bullet. WordPress is rarely a good choice for a corporate website where departments have ownership of their own segments of the website. Drupal has a higher learning curve and requires quite a bit of modification. That said, it is a flexible solution, allowing you to get exactly what you want. Typo3 was designed for enterprise websites, and therefore has the most functionality, security and reliability baked in. The interface is intuitive, and both development time and training are reduced compared to Drupal.

WordPress

WordPress was originally designed as a blogging engine, and to this day, thatís what it does best. Because it is so widely used, there are a large number of user contributed plugins to extend the functionality. The vast majority of these are either not useful or are inexpert solutions that do not create clean code or open potential security holes. Also, integration is not always guaranteed. The main benefit of WordPress is that it is fairly intuitive. It has functionality built in out of the box to add and edit pages, though the page content must appear within a fairly rigid template system.
More: wordpress.org

Drupal

Drupal is fairly modular because it was originally designed for a community website with user contributions. Think of a message board. Out of the box, it is centered around content blocks. Modules are available to display the site content in a more traditional tree format, but it is still not entirely seamless. That means the learning curve is higher for Drupal than for traditional CMS systems. For community websites, Drupal is often the best solution.
More: drupal.org

Typo3 Enterprise CMS

Typo3 is an enterprise CMS with a powerful structure based approach. A tree provides a list of content, and it is possible to add template-level blocks to the pages. One distinct advantage is that it is virtually impossible to accidentally change the overall look and feel of the site, and things like content moderation (approval for changes and new pages) is built in from the start.
More: typo3.org