many of the above are impeccable -- especially Brendel (probably first choice) and Arrau (if you like Beethoven more as Liszt's predecessor than as Hayden's successor). But I also really like Ashkenazy. He gets such fabulously muscular yet purling tone out of the keyboard, and plays with such control and command, always thinking through the piece fully. The op. 2 sonatas are sparkling and idiomatic, and the great lates are as ethereal and strage as you could want. I'm not sure why his cycle isn't better loved than it is. Perhaps he's just assumed to be a Rachmoninov guy, and his classical era stuff is consequently overlooked. Certianly his playing on the Beethoven violin and piano sonatas is superb. On the other hand, his Mozart is a bit clunky, and his Schubert is no match for Brendel's, though no one else's is either,'cept maybe Perhia.
RNM
RNM