I love Prager! I have at least six bottles of various blends of theirs in my cabinet. I always take new folks there when I'm playing tour guide, after a burger at Taylor's Automatic, in St Helena. There tastings are always fun and so less snotty than a lot of other places in that area.
I really prefer Sonoma county to Napa, as it's generally more laid back, and the tasting fees are a lot less, and you don't need reservations. That said, there are of course great wineries in both valleys and it's cool to live so close to such great wine! Yountville has 3 of my very favorite restaurants, so I still end up in both areas frequently. With the fall colors coming up I will be going to take pictures again up there very soon.
Sonoma County Vineyards by
lennycarl08, on Flickr