I returned from visiting the valley this morning. In keeping with bearshead's recommendation of hitting different areas of the valley here are a few that I enjoyed. They are listed from north to south.
Pride - Spring Mountain - north end of the valley up in the mountains. Very different from the valley floor.
Larkmead - wasn't able to make it there, but numerous posters on the forum have recommended it and the staff at Pride did too.
Pine Ridge - Stag's leap district. - small scenic winery. Nice Cabs
Pina & Miner: - Oakville on Silverado Trail ; Pina makes some great cabs, very low key tasting room, but worth it. Miner is my personal favorite winery and they treat you right. If you happen to go ask for Jaime and tell him Brad sent you. You won't regret it.
Artesa - Carneros - We thought the wines were just OK, but the property was so interesting it's worth checking it out.
Personally, I prefer to keep my tastings close to each other to cut down on the driving. The flip side is we never seem to make it out of Oakville.