I'd cite Helen Hunt as an equally awful performance alongside Paltrow. Neither broke any new ground, Hunt just played the same character from Mad About You.
Whether you like Sandra Bullock or not, she has been nothing but genial and cordial this season and her tribute to Betty White was endearing.
Also, whether The Blind Side is a bad movie or not (which I think colors people more in their opinion of Bullock in it than the performance itself), there is no denying that the film would have been nothing without her and her performance is stronger than she's given in her career right up there with Infamous. What she does in Blind Side is take a rather pedestrian film and turn it into something more. Whether you agree or disagree with the racial aspects of the film, there is a conviction with which Bullock delivers her performance and she elevates the film itself.
I don't expect anyone here to agree with me and I don't really care. I think Bullock did more interesting work in Blind Side than Meryl did in Julie Julia, a non-performance that really was nothing difficult or exceptional for Streep. I think she would have been a better winner last year for Doubt than for this trifle.
But, I digress. I think Gabourey Sidibe also delivers a knockout performance and it's really too bad more people aren't talking up Shohreh Aghdashloo as well. She is stunning in The Stoning of Soraya M. I like Abbie Cornish in Bright Star who is much better than her material (though Paul Schneider is the stand out there).
Some other wonderful performances by woman in lead or questionably lead performances: Emily Blunt - The Young Victoria, Marion Cotillard - Nine (this is a supporting perf, but has been pushed as lead) and Elle Fanning in Phoebe in Wonderland.
So, I don't think this is nearly as dreary a year for lead performances some here might suggest.
"Any society that would give up a little liberty to gain a little security will deserve neither and lose both." - Benjamin Franklin