There's something I really love about Cat Steven's voice. There are some songs of his that I cannot imagine anyone doing well, not that they include amazing vocal performances but it's just the way he sings them.
He can display such warmth, feeling, regret and melancholy, usually within one song and usually more than one of the above at once. Most of the time his voice is controlled so well and then he will suddenly have a quick outburst. Well, outburst isn't the right word. He never quite shouts, but when he raises his voice you can feel the frustration and passion steam out of him.