For those in the D.C. area I have to recommend a couple and warn you away from one.
First, Swedenburg and Willowcroft wineries are excellent. We were lucky enough to catch the winemaker at Swedenburg, who was running the tasting table. We dropped by on a Friday which was slow. We were apparently the first ones and we hung around and talked to him for almost an hour, which is always good to do if you can. Catching the winemaker, rather than someone just running the tastings or the owner, is always good. Chatting with the winemaker for almost an hour is great. And doing that with a really high quality set of wines is an excellent way to spend a Friday. We got half a dozen from there, and we got a wide variety (which is unusual - if we buy that much we're often buying several bottles of a staple).
Willowcroft was also nice. This is the oldest winery in Loudon County so they know what they're doing. This was also on a slow Friday and we caught the owner. We've had Willowcroft wines before that our friends had, but this is the first time we were at the winery itself.
Dry Mill is a relatively new one that we visited for the second or third time this trip. Always good. Cobbler Mountain is a brand new winery that seems to still be getting on its feet, but it did not disappoint. The owners are very friendly. Pearmund is a classic that should be familiar to anyone that's ventured out this way.
The one that I would caution against is Quatro Goombas. I think we got one bottle there, but we didn't enjoy their wine too much. They ship in grapes and juices from California. That's fine but if we want a California wine it seems like we'd just buy from a California winery. The service there wasn't as welcoming or interesting as some of the other wineries either. It wasn't a bad experience, but there are much better places to drop by if you're in the area.
On a related note, Kate and I are probably going to start a new blog on Virginia wine, as well as our trips (we often take in the historical sites - more than just the wine - on these trips), and our food adventures (we are aspiring foodies, but certainly not as authoritative on that as on the Virginia wines). I'll link that here if/when we get that up.