I forgot to mention that I made more updates to the site's CSS.
I made the template WAY too wide. Impractically so. I reduced it by a few hundred pixels, which seems to better suit the content. I might set a maximum width of around 850px and then make it fluid if the viewport is smaller then that. Maybe.
I also added borders to separate out the right rail from the main content, and posts from each other. This seems to make things feel a little more organized.
I still have a desire to add more things to the right rail, but I feel like the Twitter feed is enough for now. One of these days I'll go back through and tag all of my posts and add a tag cloud, as well as links to my personal favorite posts.