I've been getting wine from the
Napa Valley Wine Exchange for at least 5 years, and I recently moved our membership to the red-only one because that's what we've enjoyed most from there. Not to say that some of the whites weren't good, but my wife and I are much more partial to reds. They also send suggested recipes to be paired with each wine, some of which are incredibly good.
I've found that it's a great way to experiment with wines. Now, if you're looking for specific wineries, that's something different. I've been fortunate enough to get to know some of the wine makers over the last few years going back to a time when the wife and I were in Napa during football season, asked about the Bears game only to have the owner bring out a TV to watch the game and invite us to sit on his patio and watch with him while the Bears destroyed the Lions. He's introduced us to several other folks, and we're customers for life. It doesn't hurt that he's got one of the best Pinot Grigio's I know about.
One other thing - a few wineries are figuring out how to get around state laws. I'm thinking of La Castellana specifically (if you haven't tried Il Barone yet, you're missing out), and they're not selling their wines in stores at all. You have to have them send it to you directly, which is legal in every state except Utah since there is no other distribution method. It's also one of the coolest wineries I've been to since it's basically castle on a hill in Napa.