D7000 + 17-55 or 24-70 2.8??

Hi all

The zoom i usually use with my D7000 is the 16-85mm Nikon - which has a great range, but is on the slow side of life. So I'm thinking of picking up something faster. I'm torn between the Nikon 17-55mm 2.8 and 24-70mm 2.8. In terms of pure image quality which of these performs better on the D7000? Or are they about the same?

thanks!