Chrome: Vanilla is a browser extension that serves as a whitelist for browser cookies, automatically blocking cookies from sites you don't explicitly allow.
If you hadn't noticed, Google Chrome saves a ton of cookies. Add to that all the cookies you pick up from other sites and chances are you've got more cookies than you'd really want.
Vanilla puts you in control of the cookies that you create a simple cookie whitelist. It lives as an icon in the Chrome Superbar (address bar) and indicates whether or not the site is allowed to save cookies (you'll see a slash through the icon if not, which is the default). If you want to add a particular site to the whitelist, just click the icon and choose what you'd like to add. You'll also have the option of clearing out any unwanted cookies you've previously accumulated. If you want to whitelist a bunch of sites ahead of time, Vanilla will let you do that through its options. Vanilla's options also include diagnostic tools to assess your current cookie situation.
Vanilla is a free Chrome extension and it's available for download right now.
Vanilla [Google Chrome Extension Library — Thanks for the tip, Dennie!]