If you want to blog, then WordPress is the best open source blogging software available. OK, that's just my opinion, but judging from the press and internet, it is an opinion shared by many.

WordPress has made some great improvements from when I first used the program. One of the best improvements is that you can add themes and plugins from the admin section of your site. These are installed automatically. You don't need to first download them to your computer then upload them to your hosting site. Another great improvement is the ability to update software from the admin control panel. Again, this is done by clicking a link. The update is handled automatically without you having to download or upload anything. This ability to update automatically applies to themes, plugins and the main WordPress software.

WordPress has recently been mentioned as approaching Joomla and Drupal in terms of its ability to serve as a general purpose CMS for you website. I had used WordPress some years ago to design a general purpose company website. It required a lot of customization but was possible. I'm sure it would be much easier now, particularly with some of the better themes and with some plugin help. However, just as I don't recommend Joomla for serious blogging, I also don't recommend WordPress for a traditional company or organization website.