Rubinstein's Polonaises are excellent, especially the two most famous, A major and A flat major.
Although his A flat polonaise is naturally far from the best technically, I think brings off the sort of regal pomp of the "A" section better than any other recording I have heard. This applies to his recording of the polonaises generally. Nobody captures the nobility of these pieces better than he does.
My second favorite recording of the A-flat polonaise would be Josef Lhevinne. Its somewhat of a stunt, but it also has an incredible forward momentum. He goes faster than anybody and uses very little pedal. Definently a unique interpretation; almost classical at the same time as it takes huge liberties.
Stuill every recording of this piece leaves me unsatisfied, I'm not sure why.