Just saw "The King's Speech" last night, love it!! I agree Colin Firth is very likely to win the "Best Actor" award, even though I didn't see the other nominated movie except "Black Swan".
I also think Geoffrey Rush's performance was outstanding! Compared to his roles in "Pirates in the Caribean", I much prefer the "serious" roles he plays in the movies like this one and "Shine". He's such a talented actor (aren't all the Australian actors here great?)
I would love to see Natalie Portman win the Best Actress award. As for the supporting actress, I don't think Helena did such a fantastic job - her role is very "stereotypical", and didn't have much depth. If I had to choose, I will vote for Mila Kuniz (?) in "Black Swan". A bit over the top, but very engaging performance.
Generally speaking, this is a rather disappointing year for movies - I don't think there are many very good ones - but of course, I didn't have much time to explore even the nominated ones so I guess I can't over-generalize here:).