I was in a similar postion a few weeks ago, I was going to use Joomla but then I learned it has problems with keeping urls static, very bad for SEO.

I decided finally to go with Drupal, it comes recomended by programmers on account of its clean code. But you are right that it is hard to understand at first, however after buying and studying the book: Drupal : creating blogs, forums, portals, and community websites by David Mercer, I started to understand in a couple of day´s. It´s potential is enormous and it has a very active community behind it.
Forget about categories to begin with, it is somewhat advanced. Mostly you use modules, themes and then the create content under administer.

Use google search, >"keyword" site:drupal.org< and you´ll find all the info you need.