Who is your favorite recurring (non-team mate) Non Player Character, and why? In all three main Mass Effect games, preferably. I count Joker as a member of the team.
For instance: The guy fighting for his refund against The Company.
Or better: Khalisah al-Jilani. I love how she's such a caustically irritating person, and gives Shepard and "other" krogan a chance to unleash their rage, only to (finally) learn how to dodge--and to deliver--a sucker punch. Not many characters can claim to knock Shepard down. I also like how she can expose a more sympathetic side in Mass Effect 3.
Others?