The guys over at BlogPerfume have a look at what other free blog platforms available are next to WordPress, to host your blog with. Their list is rather complete and makes it easier to discover most alternative platforms. Handy if you want to move away from WordPress or want to have a look at all the platforms before making your choice and chose for a specific blog platform.
A while ago I published a similar but shorter list on BloggingPro. Although I only mentioned the then poplar options, I went a little more in-depth and compared pros and cons of listed platforms.