About three years ago, after Irreal was hacked, I published a short article on securing WordPress sites that pointed to a WordPress article on ways to harden a WordPress site. Recently, John Stevens wrote me to say that he and his Hosting Facts team have written a follow up article that expands on the theme of the WordPress content.
If you're using WordPress for blogging or some other CMS function you should definitely take a look at Stevens' article. It has 28 tips on how to harden your WordPress site. Many of those are the normal things that you'd expect but there are also some suggestions that you may not have seen. It's definitely a useful resource.