I am thinking of taking a trip to somewhere in Mexico with my girlfriend for her birthday. I've been looking at Puerto Vallarta, Playa del Carmen, Cancun, Cozumel, and Cabo San Lucas. Every one of them has an LCDH (I checked, haha, it's my one requirement). For those of you with experience, which one would you prefer, where are good places to stay (We can't afford anything real expensive, but don't want to stay in a dump either), etc.?