Napa or Sonoma wineries. As I remember, Folie a deux (Napa) had a decent Syrrah. I like Ravenswood (Sonoma) reds as they were relatively cheap & all Big & bold (No vinos sin huevos is their motto). Pricier stuff from Grgich Hills, Far Niente, and Stag's Leap. Lodi has some decent wines (mainly Zinfandels) that are relatively cheap. Never got into Pinots, but there are some Southern CA wineries that are known for their Pinots. Best Cabernet Sauvignon I've ever had was from Far Niente ... never seen in a store, they mainly sell direct to higher end restaurants. Francis Ford Coppola used his "Godfather" profits to buy two wineries (the old Inglenook which had devolved to "Gallo" type jug wines) and Niebaum/Coppola. He gets good reviews, but I've always been disappointed except for his more expensive (outrageously) stuff. Opus One is also highly rated, but as I remember, they are mainly a blend as opposed to single grape varietals.
Most of this stuff will be direct from Winery or expensive restaurants, but occasionally, Costco or Sam's will get a few cases ... problem is their storage. I've had some expensive wines that were "cooked" in southern Costco/Sam's warehouses.