TravelGround >> Non-FRAT places in Mexico?

Any ideas on good places to go in Mexico (non - Spring Break type shit). I've done Sayulita and San Jose del Cabo - both of which I liked. My girlfriend is probably going to want to go the "all-inclusive resort" route, but I don't want to be in the middle of a frat party. We're on a pretty tight budget - anyone know of a place that can balance price, location, and accommodations?