Picking two per game, because I can't pick just one.
Origins: Alistair and Loghain. Loghain is such an interesting, complex character. Alistair is my closest friend and brother-in-arms.
Awakenings: Nathaniel, because a human noble the interactions with him are great. And he has the most interesting arc, in my opinion. Sigrun would be second.
DA2: Varric is so far and away the best. In fact he's my #1 character in the whole series, for reasons I don't think I need to explain. Carver was actually my second favorite. Despite his abrasive attitude, he felt realistic, and I like a character who doesn't constantly agree with me and think I'm great. And when he joins the Wardens and finally sees himself as an equal, it completes a great character arc. I liked that he finally found his place in the world.
Inquisition: Cassandra is such a layered character. I find her weakness for "smutty literature" adorable, the strength of her convictions, and her idealism of what the Chantry should be. She's probably my second favorite character in the series. Picking Varric again feels like cheating, so I'll say my second is Solas. My Inquisitor disagreed with him a lot, but I always appreciate his perspective on things. Also: