The best addon ever... period Rated 5 out of 5 stars
If I could only pick 1 addon, this would be it, edging out NoScript. But it's only as good as the subscription lists you use. I recommend, at minimum: "EasyList", "EasyPrivacy", and "Malware Domains". The rest is different strokes for different folks. I don't do social networking. No Twitter or Facebook, and get tired of seeing buttons asking me to link everything I ever do on the net to those accounts. I only use Youtube, and even then sparingly, and only watch not make vids. So I use a sub list called "Antisocial" as well that cuts out a lot of those syncs that irritate me. Those 4 only. To large a blacklist can slow you down, so don't go overboard.
And uncheck all the slow filters too... the ones with snail symbols to the right of them. And IMO everyone should be made aware of the check box in the bottom left hand corner to allow "some" unobtrusive advertising. It's up to you whether to utilize it or not, but people should be aware that it's there anyhow, and allow them to make an informed decision. As opposed to trying to keep them oblivious to it. I personally uncheck it.