Everyone should know by now that Firefox allows you to do some pretty coo, things by editing configuration files and changing user style sheets. If you are really good, you can change the look of a particular site a bit, however if you wanted to change the way a site like Gmail looked, good luck to you. With hundreds of stylesheets (1500 odd last I heard), it would take you a fair while before you got it looking any different. Enter Stylish, a great firefox plugin, which allows you to manage your user styles easily. According to the site
Stylish is to CSS what Greasemonkey is to JavaScript, and unlike other methods of using user styles, most styles take effect immediately.
They have a massive site called Userstyles.org, which is a collection of styles that you can apply to popular websites. I played around with this thing today, and installed the Gmail Redesigned stylesheet which makes my gmail look something like this
There are a lot of styles to choose from, and so far, I have already change the way wikipedia, gmail and google image search look!
