It takes some time to learn (not too if you have dealt with any other CMS before, mainly selecting options) but you can't really go wrong with Wordpress. At worst, you don't like it and didn't have to pay to try it. You can use it for something real basic, or customize it like crazy to get some pretty impressive setups. The community is solid (check the forums over at wordpress.org) and there is immense support for themes and plugins (both free and paid). There are also quite a few plugins that help port it into an existing site that uses popular software, such as linking it into Joomla or PHPbb. It has been around a long time, is continually developed, and is the most popular blogging software for a reason.