Create, convert and/or set-up blogging tool

Our current blog needs to be migrated.? The blog URL is:? <[login to view URL]> I want an easy-to-use yet versatile open-source blogging tool set-up on our server so that we can migrate away from the limitations of using Google's [login to view URL] tool.? I also want the blog to use the same design? as the articles on our website.? See? <[login to view URL]>? as an example.? Whoever wins this work will need to convince me they know what they are talking about.