My pick hands down would be Eric Asimov from the NY Times.
Not only is his writing clear and concise but he always manages to get the story behind the wines. His articles are always a mix of people, place and how the wines taste. He includes the food editor and local sommelier to conduct tastings and the web interactive feature offered online with the articles are just stellar.
Crisp, Refreshing and Greek is his latest. kybecca happens to have his top pick as well.