Agree about the shoes and the suit. You have to know your audience. If you come to an interview not dressed appropriately, it tells me you haven't done any research of the company you're applying to. You came unprepared, and that's a strike right off the start.
If I ever were to run a McDonalds, and one kid came to me in baggy shorts and some kind of trashy t-shirt, and the other comes in khakis and a polo, I'm hiring the kid in khakis and a polo. He's the one who took the time to prepare to make a good first impression. If he's willing to do that before he even gets the job, he'll probably make the better employee.
Always, ALWAYS dress better for the interview than what you know the company dress standards to be.
My industry has become very casual thru the years. Button shirts is generally as fancy as we get, unless we're interviewing before a client. Then it's shirts, ties, and a sport coat. And yes, polished shoes. You have one shot to make a good first impression. Why even let the way you're dressed come into play?