For actresses, once we've got the obvious Merryl Streep out of the way, there's still some excellent picks: Jessica Chastain is great and is going to have a brilliant career, as is Jennifer Lawrence. Cate Blanchett and Charlize Theron when they can be bothered. I have a soft spot for Amy Adams and Judi Dench. I don't rate Scarlett Johansson that highly but I haven't seen Under the skin yet.
Kathy Bates and Jessica Lange are brilliant as well. I like Robin Wright also and Rooney Mara as given some great performances.
Carey Mulligan could become one of the greats as well. Elisabeth Moss shows great range in Mad Men but I'd like to see her be as good in something else. I've heard a lot of great things about Shailene Woodley but only saw her in White bird in a blizzard (in which she was excellent), so I haven't really seen enough of her.