"How do You want to Google today?" - this is the tag line of the free software (GPL) - CustomizeGoogle.com. This firefox extension 'injects' additional code into webpages to enhance its functionality. Imagine able to remove even text-ads from google services like gmail, froogle and even google search itself. Take a look at these screenshots to see what that looks like. And that the tip of the iceberg. You can do a lot more. For more details, visit customizegoogle.com or the extension home page.
Sadly (sigh..) non-firefox users are going to have to sit this one out.