I just went for the first time in Oct.
Personally, I would suggest looking at Sonoma, and then driving over to Napa one day. Sonoma had a much more relaxed feel to it... not as touristy either.
We stayed at the Inn at Sonoma. It was a great value... very nice place, very nice location. You can do wineries during the day and easily walk to lots of restaurants for dinner in the evening so you don't have to worry about driving.
http://www.innatsonoma.com/In Sonoma I recommend Viansa and Gloria Ferrer. Viansa is a great place to picnic for lunch. You can get everything you need there.
In Napa I recommend Frank Family (great Chardonnay and sparklings) and Chateau Potelle. Potelle is off the beaten path. We didn't care for their wines but the scenery was really nice.

[This message has been edited by ada8356 (edited 12/10/2007 12:37p).]
[This message has been edited by ada8356 (edited 5/13/2010 12:51p).]