Been there done that!! (Not the cooler mishap, but the details afterwards!) Seriously, we love Mexico and the Mexical culture and food. We usually stay at all inclusives just for the pampering, but spend quite a bit of time in town and diving. I guess everyone has their travel stories. We always focus on the best parts and tend to "forget" about the less enjoyable times!
Do you do alot of diving in the Austin area? We've done some lake stuff down south, but mostly around San Antonio (Travis, Medina). We live in Abilene. We have to travel to dive - nothing clear around here!! New Mexico has some pretty good spots as well.