I'm rooting for Milk, and I'd like to compare it to two other nominees: Frost/Nixon (also nominated for best picture) and Happy-Go-Lucky (nominated for best original screenplay, though Sally Hawkins won best actress at the Golden Globes).
So, Milk vs. Frost/Nixon. Frank Langella and Michael Sheen made Frost/Nixon very watchable for me, but the production has an unpleasant Hollywood lustre. The plot arc is uninteresting and clearly imposed on the story in order to make a movie of it, and the intellectual laziness of the whole thing becomes obvious in ridiculous pseudo-interviews, where the characters are interviewed, reality-TV documentary style, as though we are watching period footage that happens to star the actors. The film betrays no consciousness that there is any problem with this.
By contrast, Milk seems to me serious-minded and conscientious at every step, both in its desire to be adequate to its sources and in the effort to reach a broad audience. I won't further sing the praises of this movie, since it's already been done plenty of other places -- for instance, in J. Hoberman's Village Voice review.
Then there's Happy-Go-Lucky. It occurred to me while watching Milk that there's a great affinity between these movies, inasmuch as they both treat (among other things) what it is to care for people, and the limits of this care. Sean Penn's Harvey Milk and Sally Hawkins' Poppy relate to other characters, often other characters who need them in some manner, in what are really exceptional ways for these times of inhuman cinema. These interactions don't just humanize the central characters; they also make the other figures persons rather than just cases. In each film there is one person who really does become a case, and an intractable one, and in each film it's mostly through gesture that we see how one might disengage when care is impossible.