Serdar Yegulalp reveals hidden configuration options in Mozilla Firefox (via E@zyVG). Firefox already gives a lot of configuration options, but it has many more under the hood. The article shows how you can use some of them to customize Firefox to your liking.
You can type
about:config in the URL address bar and that brings up a nice list of configuration options that you can modify. You can customize looks, behavior and even reduce the memory footprint of Firefox. Good article, though I believe that all hacks might not work for you. Especially the trim when minimized has known not to work on Vista.
One more recommendation I would give is to use Swiftfox if you are on Linux. It does make a difference.
However, give the options a try, especially if you have problems with it. This also says something about making your application configurable. Whether exposed or not, configurability always helps.