Which of the following decades produced the best music?

[traininthedistance]

In terms of stuff that you'd actually hear on the radio, the consensus that the 60s and 70s tower above all other comers is, indeed, the correct one.  Hard to top classic rock and Motown.

I would also consider the 2000s to be a worthy choice, half on the grounds that a lot of my favorite "alternative" and indie pop acts peaked at that time, and half on Tik's grounds that there's just so much stuff being made and so much easier accessibility in the past decade-and-a-half.  

In terms of pop music, the 50s (or earlier) and 80s are obvious laggards.  Rock and its cousins was still just too undeveloped, without much complexity or artistic impulse, until the mid-60s; and while the early 80s had some great New Wave and other classic rock-type things (Elvis Costello, Talking Heads, Paul Simon [yes, Paul's 1980s work was among the best of his career]), the late 80s were just a nuclear wasteland in every genre as far as I can tell.

Obviously this all gives very short shrift to jazz, classical, and other such "art" genres.  Muon's right that jazz probably peaked in the '50s, and obviously classical owns every decade before that.  But, as much as I do actually love classical, and 20thC stuff to boot, I just can't think of it in terms of decades, so I'm leaving it out.  I also happen to think that classical today is pretty good, and has recovered from its postwar nadir artisticially, even if contemporary stuff has next-to-no marketshare.

[traininthedistance]

I also happen to think that classical today is pretty good, and has recovered from its postwar nadir artisticially, even if contemporary stuff has next-to-no marketshare.

Though even the idea of a postwar (composition) nadir is kind of questionable; of course you did have the... um... absurdities of the Darmstadt School, but you also had (for instance) pretty much the entire career of Benjamin Britten.

It is to my great embarrassment that I must admit I've never really been able to get into Britten.  I think part of the problem is that his greatest skill seemed to be with operas and vocal music, and I happen to not really care for those forms much as a rule, even when the language barrier isn't a factor.  I much prefer instrumental works for the most part.

Also worth noting that his contemporaries who stayed within a more-or-less tonal idiom tended to be, well, hacks like Walton, so as a whole the era still suffers.