Good suggestion non-amos. As a jazz lover, I have to agree.
It's true that blues can be a plural - "Look at the blues in that painting." Or, in Australia: "There are blues breaking out all over the ground." (Blue = fight, or argument.) But blues is distinctly a word in its own right, in the sense of a sad feeling, and a musical form.
In fact, I believe it qualifies as a common word.