In addition to Adblock Plus and NoScript, which you already mentioned, I most frequently use:
- Cookie Monster. Gives you quick options on which cookies to accept or reject rather than turning them on or off globally.
- Sticky Password Autofill. Browser counterpart to the Sticky Password manager.
- TabMix Plus. Improves tab options.
- HTTPS-Everywhere. Automatically switches to HTTPS on supported sites.
- Ghostery. Selectively blocks trackers from ad companies, social networks and such.
- Better Privacy. Blocks Flash cookies ("super cookies").