I loved Slumdog Millionaire - in fact I watched it twice which is a rarity for me. And I wouldn't mind watching it again. I liked everything about it - cinematography, acting, script, etc.
Frost/Nixon was very good, I thought. I really enjoyed it because I liked the characterization of Richard Nixon which came as a surprise to me. I always thought I just wouldn't like Nixon as a person - but the depiction of him in this movie elicited a real liking and interest in his character.
Milk was good. It was an interesting plot - but I didn't enjoy watching Sean Penn in that role and I usually really like Sean Penn as an actor. He was just a little too stereotypically over the top and grating - so I was glad when that movie was over. I remain glad that I watched it however.
So my rating of these movies overall would be:
1) Slumdog Millionaire
and that's how I would rate them in terms of actors, directors, scriptwriters and cinemetographers as well.