EasyBlog has steadily become the standout extension in the Joomla blogging world. With EasyBlog you get a full featured and complete blogging platform with available extensions ready to plug in for even greater functionality.
StackIdeas caters to the Joomla blogging community by producing quality extensions and offering superb support as well.
EasyBlog starts at $59. Demos are available on the StackIdeas site as well.
Also from StackIdeas is a great commenting extension called Komento. If you already have a Joomla blog, this free extension is a really nice way to add comments.
Just a few of the many Komento features include geo-location, email notifications, enhanced security and the ability to attach files within comments.
For a full list of features and a demo of the product, visit StackIdeas.com.