Firebug lets you edit individual web pages locally, with live updating so you can see the effects of your changes right away. Unfortunately, these changes are lost after the page is refreshed.
Is there any way to make these changes "sticky" in some way, such that repeated visits to the site would reload your own customized html/css that you edited? I’m thinking perhaps some sort of Firebug feature that I’m missing, or another plugin of some sort…
Just to be clear, I’m not talking about websites I have server side access to. I would simply like to be able to reposition the content of some pages I visit frequently so it fits better on my monitor setup, which I can do in Firebug but I have to do it every time the page loads (I would like to be able to avoid having to do that).
You should make use of the Greasemonkey and / or Stylish addons for Firefox.
These where originally developed to do exactly what you intend to achieve.
Also check out this article on how to get started with Stylish.