For me, it doesn't get any better than the late piano sonatas of Beethoven, especially Op. 109, 110, 111. This is music preeminent and unsurpassable, though some of Brahms comes close. Here is Claudio Arrau performing the First Movement of Sonata 32, Opus 111.
I am a musical elitist, but not a snob. An elitist in that I maintain that such popular genres as blues, jazz, folk, rock, and so on are not music in the eminent sense: they do not speak to what is highest and best in us. Or at least not in their typical manifestations. I admit that there are some exceptions. Example. But there is nothing wrong with popular music's being geared to our lower self. The claims of the lower self have their limited validity. Not a snob, in that I enjoy and appreciate music of all kinds, with only a few exceptions.
To say that the best of the blues is the equal of the best of Beethoven is a bit like saying that the best of Carnap is equal to the best of Plato. Either you see what is wrong with that or you don't. If you don't, I can't help you. Here we enter the realm of the unarguable. Positivism is to philosophy as muzak is to music. Positivism is to Platonism as blues to Beethoven.