First, ol' Percy himself, Robert Plant, 55 today. His solo career has had its share of ups and downs, but at least he's always been determined to follow his muse and not crank out product. Of course, he's already earned his place in Rock and Roll Valhalla for his idiosyncratic vocals as Led Zeppelin's frontman.
Next, a somewhat less famous (but no less important) figure than Plant, John Hiatt, 51. Even though he's never had much success as a solo performer, many artists have gone on to have huge hits with his songs, most notably Bonnie Raitt with "Thing Called Love". Favorite album: 1997's Little Head, another album which most regard as one of his weakest. Seems to be a trend with me.
Finally, none other than seminal horror and fantasy writer H.P. Lovecraft, who would have been 113 today. If you've heard of the Necronomicon or the “Cthulhu Mythos”, well, he's the bloke what created 'em. Hopefully, he didn't go on to encounter anything he wrote about.