Just got back to NYC from a trip to the Bay Area and, while I had done some pre-trip research on this board, I didn't do quite enough. We eagerly galloped into La Palma Mexicatessen but trotted away disappointed - no more potato chips! (I had missed Jim's post last month on the subject.) The pupusas (mixed) were delicious, though.
Fortunately, we had earlier hit Taqueria San Jose in San Rafael, which was as great as I had remembered from my last visit there a year ago. The horchata is UNBELIEVABLE. If I lived nearby, I would need to stop in every day for a big cup.