Install this add-on: https://addons.mozilla.org/en-US/firefox/addon/cookie-monster/

In it's default configuration, it blocks all cookies, so click the toolbar button for it and choose to allow whichever sites you want it to remember.

After you install it, click the Firefox button, go to Options | Options | Privacy and in the top dropdown menu, choose "Use custom settings for history".

In the list of boxes underneath that, remove the checkmark from "Accept Cookies from sites" because the add-on will manage that from now on. For other options, see Using Custom Settings

Incidentally, some of your add-ons are out of date which exposes your machine to exploits. Please visit the Plugins Check page and update where necessary.

Rather than getting rid of the double-click cookies, I would first concentrate on not creating them in the first place by installing the Adblock Plus extension and by installing a good hosts file. Adblock Plus will not work without filters, so after installing subscribe to the EasyList US filter.

• Removing unwanted content on webpages - MozillaZine Knowledge Base
• Blocking Unwanted Parasites with a Hosts File