I've been tempted to try that Concha wine (they have it at Costco right now). Another fantastic wine I found at Costco is Katherines Chardonnay from Cambria. I'm not much of a Chard fan, but it is very nice ($11 at Costco).
The red that I just drool over with Mesquite grilled/smoked beef is Montignana Chianti Classico Riserva 1995. No idea of the price at MSRP, got it clearanced at Albertsons!