This Style will remove the ads on the right of the screen in GMail and expand the message area to fit the entire screen. I threw this together really quickly, so I did this using a major no-no: negative margins. So far I have not experienced any bugs, but if you have a different screen resolution you will have to edit the margin on the last line of code.

THIS STYLE WORKS ON THE NEW VERSION OF GMAIL ONLY

****WARNING****
this script will remove the special context features which GMail has, such as "map this", "add to calendar", etc. These items are blocked by the same method as blocking the ads.