If you're unhappy with Facebook's new small font size (or other annoyances), user script Better Facebook gives you over 75 extra options with which you can tweak Facebook to your liking.
Every time Facebook redesigns their home page, the entire internet seems to erupt (usually unnecessarily) in anger. Recently, however, Facebook changed its default font size for the news feed to a smaller font that is significantly harder to read, and it's a pretty legitimate complaint. Luckily, user script Better Facebook has you covered with a new feature that allows you to force a certain font size.
We've mentioned other Facebook-altering user scripts like F.B. Purity before, but if you're looking for something to drastically change your Facebook experience, Better Facebook will do it. It brings a new interface featuring tabbed news feeds, extra sidebars and a humongous options pane to Facebook, from which you can manually filter your news feed, hide read posts, highlight comments, see who's unfriended you and much, much more.
Note that while Better Facebook has a bunch of neat options, it really changes how Facebook looks, and you might not be happy with how drastic it is (I know I personally wasn't). What's nice, though, is that as a simple user script, you can uninstall it with one click if you don't like it. Be sure to root through the options, though, as you may be able to tone it down more to your liking as well.
Better Facebook is a free download, works in Firefox, Chrome, Safari and Opera.