I currently run Ghostery alongside Disconnect and Facebook Disconnect Chrome extensions, mainly because I'm not sure how their feature set overlaps. Do the latter two offer anything that isn't already included within Ghostery's fuller feature set? Is there a better Chrome extension than Ghostery for my purposes?
Ghostery and Disconnect act as content blockers (if you've enabled blocking) and their innards are very similar. Heres an answer I provided recently on Ghostery support board:
Outside of that Ghostery offers a bunch of features that Disconnect does not at this point. They are: click-2-play overlays (for when you wonder where your comments and videos may have went), surrogates (when Ghostery blocks a tracker, it can provide a dummy script that replaces previous one so sites do not break), knowledge pages (so you can learn about the trackers), and much more.
AFAIK, Disconnect replaces Facebook Disconnect, however, if you only want to block Facebook, you're better off with just Facebook Disconnect.