Install the Adblock Plus extension to your browser and then add these custom filters. That’s it! No more Facebook on every site you visit.

||fbcdn.net^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||fbcdn.com^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||facebook.net^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||facebook.com^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net

I had this somewhere on the site for when I change browsers, but lost it. Found this originally on Lifehacker. Thanks Whitson!