Francisco makes some interesting points about beauty in his post here. While I too will gladly stand up for the use of folk music at masses (though not "Eagles Wings" - yuck), I think he goes a bit far, both by dismissing the important role beauty plays in our knowing the true and the good and by making beauty something totally relative.
As to the first, the author of the article makes the point that beauty is the catalyst for our pursuit of goodness and truth. That is, "Without beauty, truth becomes legalism and goodness becomes moralism." Beauty is the thing that makes us, as humans, attracted to the true and the good. It awakens us to the desire. It is the thing that moves. A person can tell me something true, but without it being beautiful, I won't care. I can realize something is good, but without beauty, I won't do it. As a result, the Catholic Church's mission of teaching the true and the good can only occur in the context of the beautiful. It is what gives us ears to hear the truth. It is what gives us the will to do what is good.
And for the second, to say that beauty is pluralistic is not to say that it is relativistic. That is, the fact that some things move me more than Francisco, and vice-versa, does not imply that nothing is objectively beautiful. Honestly, I think it is kind of like Kraft's point about lay movements: there are several good lay movements, some which move me more than others. But there are also some movements that teach heresy. A great many might be objectively good, but there are still some that are objectively bad. And a great many things are beautiful, but there are also some things that are just plain ugly.
Perhaps more importantly to me personally is what this kind of a view of beauty does to art education. The entire idea behind art education is that something is objectively beautiful and that we can be taught to better appreciate it. But if there is nothing that is objectively beautiful at all, there is no point in being taught to appreciate one thing more than another. Preference reigns supreme. I think this strikes me so strongly because art, particularly music, is something I'm only now, as an adult, learning to appreciate.
Even after gaining an appreciation, the best art takes patience and attentiveness to get its beauty, while pop stuff is immediately catchy (though often superficial). For instance, when I was first given a copy of Sufjan Stevens' Illinois, I couldn't stand it. His eight minute "orchestral folk" songs seemed strange and noisy, and I longed to be back among my three minute, always catchy pop songs. Now, though, after roughly a thousand listens, the album stands among my favorites. And it is without question a beautiful work of art. I stuck with it because I had people who I trusted to have an eye/ear for beauty telling me it was beautiful, even when I didn't get why. But if I had accepted that beauty was in the eye of the beholder, I would have had no reason to wait, to educate my sense of beauty. And I do believe that I know God better as a result.