For the Beethoven sonatas -- the New Testament of solo piano -- I prefer Annie Fisher. Her playing is full-blooded, passionate, engaged.
Among current pianists, I find Vikingur Olaffson compelling, especially in Philip Glass. His technique is staggering.
Another contemporary player with impressive command of the instrument is Marc-Andre Hamelin. His recording of Frederic Rzewski's "The People United" is a blast.