Must-have music?

Let's have an open forum: name a musical group (or composer) you think everyone should hear. This can be a longtime love, a recent obsession, or a personal advertisement; whatever you wish. A little bit of description of what kind of music they make would be helpful too.

Then I, and others reading this, can rush out to our libraries and record stores, or at least the Amazon.com "listen to samples" features, and find some new tunes.

My own recommendations? Well, lately I'm working my slow way t...