If you use either the Greasemonkey or Stylish Firefox extensions, I have the perfect extension for you when it comes to getting a little more browsing room while using Google Reader.
Just load this bad boy up via either one of those extensions and you should be good to go.
So where does it save you the room? Well for the most part it looks like it just cuts off the Google stuff from the top and gives you the “full view” of the reader. This is nice if you just hate seeing that Google Reader logo at the top every time you login.