One of my favorite places while visiting out there was the Dry Creek Valley, which if I'm remembering correctly is pretty convenient to Healdsburg. I thought it was a very picturesque, well defined valley, and it didn't seem too over-developed. And it had some great wineries, including Ferrari-Carano, which easytraveler mentioned. I don't know about their pinot grigio but I think their fume blanc is a wonderful value.