Ralph Vaughan Williams. To begin with, I'm an anglophile, and a sucker for vaguely celtic-sounding melodies. Also, I like how unabashedly populist he is. There's isn't a shred of pretension in his music, everything's simple and melodic (at least at first listen), even at the expense of form, his fantasias being a prime example. It's all so direct and accessible to even an uninitiated listener that you can listen to it for hours at a time without getting tired.