Claudio Arrau is the philosopher of pianists. His 1960 recordings set the mark for anything that came afterwards and I don't think he has been equalled yet.

Wilhelm Kempff's first complete cycle, recorded in the 50's in mono. Mandatory listening!

Stephen Kovacevich, one of the newest sets. Good sound, rather aggressive performances, but fascinating at any cost.

Brendel's first for Vox, available in four volumes. The entire second cycle (Philips) is still available at Amazon.de.

The classic standard for Beethoven is Schnabel's set from the 30's. Few pianist nowadays, maybe none, play as beautifully as Schnabel, nor as excitingly. Look for the Naxos remasterings.

This cycle was recorded live, and while the sound isn't quite good, Ciani's performances can be revelatory.

Gulda II on Amadeo, now repacked by Brilliant Classics. Many people's favourite (though not mine), and a great bargain.

Buchbinder on Telarc.

Andrea Lucchesini, a new cycle.

Eric Heidsieck on French EMI.

Alfredo Perl, in a now hard to find set.

Annie Fischer on Hungaroton.

John O'Conor, on Telarc.