The Pathétique (op.13) is one of the most recorded sonatas around -- a warhorse. That means that great recordings of it abound, so you should also consider the other works on the cd with it as well as the pianist. After that, considering the sound quality becomes more or less important according to your taste. Rather than suggest a single volume from a complete set of sonatas, I suggest looking for recordings of Beethoven's "named" sonatas. That way you can get a very fair sampling of the composer's other works, and perhaps find a new sonata to love. Thus, my suggestions will not include the volume from Annie Fischer's cycle (one of my favorite Beethoven sonata cycles) because it is coupled with two lesser early (Op.2) sonatas. Instead, consider such cds as Wilhelm Kempff's cd with the Pathétique, Mondschein, Appasionata, and Waldstein (DG) which will give you a fair survey of Beethoven's works from the early period of the Pathétique to the middle period works (Waldstein Op.53 and Appasionata, Op.57). Rudolph Serkin also has a notable recording of named sonatas as well. Emil Gilels also has a cd of the Mondschein and Pathètique as well as another of the Waldstein, Les Adieux and Appasionata on DG that are notable, and available very cheaply in the amazon marketplace. I wouldn't get only one as it's not a lot of music for a cd, the two can be obtained for bargain prices, and Gilels is really phenomenal in this repetoire.
I also have a recording by Ivan Moravec of named sonatas (Pathétique, Appasionata, Les Adieux, Waldstein) which is oop, but very desirable if you can find it. Moravec is certainly one of the great Beethoven pianists around.
And finally there are the HIP recordings of the sonatas on fortepiano, of which the most easily obtained are those by Ronald Brautigam. The use of the fortepiano may not be your cup of tea and the Pathétique is not coupled with other named sonatas, but if you are into original instruments, then I have to recommend this because of its exemplary quality both in terms of performance and sound. Another great recording on fortepiano of the Pathétique is by Paul Komen, which does not quite match the Brautigam for sound quality but certainly equals it in performance.
Note: The Kempff and Serkin cds are usually available at BMG music clubs. Also, be sure to get the Serkin recording that lists the "extra tracks" (expanded edition) otherwise the cd doesn't contain Les Adieux. Also, the Brautigam is available for download from Amazon if you wish to sample it.
I located the reissue of the Moravec sonatas at CDUniverse.com! That's quite a nice find.
