I saw it yesterday, too. I thought it was quite good, actually. I know what you mean about its leaving you cold - I kind of feel that way, as well. But not because I think the characters' actions didn't fit - I thought they did so well that their actions were totally believable. The only problem I found with it was that Bill Nighy's character didn't have enough reason to have so much disdain for Barbara at the time he lashed out at her when they were on their way to the play. Later he did, sure, but at that point, I thought his words were overly harsh.
I saw The Last King of Scotland today. I had been basing my opinion on Forest Whitaker's performance being legendary on seeing the trailer alone. I learned today that I was right. That was the kind of performance that actually enriches your life just to see it, which is especially admirable considering he played a.) a real historical figure and b.) a monster. I thought James McAvoy was really quite good, too. Too bad he had to be the counterpart to that role - no matter who you were or how well you did, Whitaker *owned* every scene. Hell, even the ones he wasn't in.
It was a much better-done movie than I expected, too. I kind of expected a tour-de-force performance in an otherwise mediocre movie. Instead I got a tour-de-force performance in a great movie. What a fantastic character study about how power can so easily corrupt, and not just Amin, but the fictional doctor who started out being so believably (but not cloyingly so) idealistic.