In addition to NoScript use the RequestPolicy extension for Firefox. It's like NoScript with the option to allow/disallow requests of any kind that aren't directed at the current web page. For example, if DoubleClick has a pixel bug on facebook.com, visiting facebook.com with the extension enabled will not load anything from doubleclick.net, google-analytics.com, etc. and will flag it for you to allow/disallow. NoScript, RequestPolicy, and BetterPrivacy (to block/delete Flash cookies) should take care of 90.69% of the stuff that's out there.