Joomla, Drupal, Wordpress, or ExpressionEngine?
nick-dap: I had a terrible experience trying to extend Joomla. The code is a freaking mess. I would not consider Joomla to be a viable solution for anything.Lately, I've been using Drupal and it is monumentally better. The API (really the hook system) is small and flexible. There is a module for almost anything you can think of. Nine times out of ten you don't need to do any coding at all to get almost any behavior imaginable (CCK and Views alone are tremendous). As an added benefit, the community is very strong and receptive.Having said that, if its a simple blog, Wordpress is probably your best bet. Its a bit friendlier out of the box from a user perspective. I have no experience coding for Wordpress and I don't have any experience with Expression Engine, so can't comment there.