Wordpress is not “the best” because there is not just one type of application for a CMS. Wordpress may be the best in its field but every CMS has its stong and weak points. It really depends on what you want to do.
Look into http://www.opensourcecms.com/
– at the left you will notice a distinction between “Portal/CMS” and “Blog” (“Lite” might be interesting, too, for simple sites without database) – and this is exactly the point: What’s your site gonna be? Primarily a blog or a “regular” website?
Just try out the demos on the page linked above. The star rating might help in what to check out (choose software with many votes and high ratings as these are probably the most accurate evaluations for a first glimpse).