what is good music?

good music is like good sound

OK, I'll bite. If the music is good, from moment to moment I don't know what is coming next.

This doesn't hold true for recordings I've listened to many times, obviously. For these, I think what makes them "good" is the elegance I perceive in the artist's solutions to the problems posed by the musical structure.

If that doesn't make sense, what I mean is this. Each musical moment is a statement. The next moment has a relation to it. The artist's decisions about these relations are what I am calling solutions to problems. The sum of all these relations or connections is musical meaning.

Somebody has said the above, and more, much better elsewhere, but hey, I bit.

any music that 'moves you' is good music. its a spiritual thing

I can't define it, but I know it when I hear it.

With respect and credit to Potter Stewart.

I find "good" is not the right word. By your definition something like Schnittke's 2nd violin sonata would be "bad" music, which this piece is anything but. It is highly dissonant, highly atonal ( though it is not readily serially atonal), there is no melody. In fact near the end,
the accompanying piano strucks in the C major key, the basic C chord in all its glory and loud. Wow! Here is the most basic of basic stuff, and it was so out of place! Probably the most gratifying concert I have ever been to yet the piece played would hardly be called "good". So it is more of the aesthetics of music as art, that determines whether the piece is "good" or "bad".

In the world of Adorno, the dialectical master of musical aesthetics, the commercial side of music, he deemed corruptible and not worthy of being considered, it was all "bad". However I take a different take on commercial music, it is just a form of entertainment, just like TV or football, whether it is the Beatles or Nirvana or James Brown or any rap group, its only entertainment in the form of music. So enjoy it and relax, and as the Stones' said..."it's only rock and roll!"