Out of the 3, which one would you pick? --> Assume that Request Policy and NoScript are not available.
Even if one is using RequestPolicy and/or NoScript, one should also use at least one blacklist scanner. RequestPolicy doesn't block anything on the current domain, and both are "all or nothing" per domain. Blacklist scanners can do partial domain blocking, including on the current domain.
I used to be a fan of Ghostery in the past unfortunately that changed the moment Evidon bought it and made it a tool for advertisers. Personally i don't care how much better it blocks stuff (which it doesn't plus it's heavy on CPU resources) or if it has more features from similar tools or if you have the option to Opt-in the "GhostRank" all these are completely meaningless and irrelevant to me. Either you want it or not by using Ghostery you give your support to a business model that basically exploit the user, and for that reason alone i refuse to install it on any of my machines. Disconnect for me.
I had been using NoScript and Adblock Plus with EasyList and EasyPrivacy subscriptions. I've added Ghostery and RequestPolicy 1.x recently. They all seem to work fine together. If you're wondering why I use all of those, please see https://www.wilderssecurity.com/showpost.php?p=2312099&postcount=17.
I assume the OP is talking about Firefox. NoScript and RequestPolicy are among the best for power-users. If one is not interested in such a degree of control, one can use NoScript in Allow Globally mode and RequestPolicy 1.x in blacklist mode instead. If one wants 'easy', ABP with EasyList and EasyPrivacy filters. One can always disable the 'Acceptable Ads' option or use AdBlock Edge (if one doesn't agree with EyeO's business model) Among the 3 options in the poll, Disconnect and Ghostery would be my choices. Some might feel uncomfortable with Evidon's business model and "GhostRank" (despite the feature being opt-in).
I'll give an example for page http://profootballtalk.nbcsports.co...ts-first-postseason-win-with-broncos/related/. Connections to wp.com and wordpress.com must be allowed in RequestPolicy for this page to be displayed properly. With connections to wp.com and wordpress.com allowed, Ghostery blocks hxxp://s.stats.wordpress.com/w.js?21 and hxxp://stats.wordpress.com/b.gif?v=noscript, and the page displays properly.