Well, it's hard to argue with Argerich's Liszt Sonata, which has always, until recently, been my favorite performance on record. But, a new recording by Arnaldo Cohen, I think, begins with her astonishing techinical mastery and supercedes it with an expressiveness that, I feel, Argerich sometimes throws aside in her breathless dashes through the supreme technical hurdles of that piece. Cohen's new recording is on Bis and includes a "Vallee d'Obermann" that even outdoes Horowitz. He has a gorgeous sound and a great singer's way with line.
All that said, Joyce Hatto's recording of the Prokofiev War Sonatas out distances both of these colossal artists. She is surely the most ignored and underrated pianist of our time. Such a mystery!