Best beaches I've ever been to were on margarita island (it's not just a clever name):
http://en.wikipedia.org/wiki/Isla_Margarita
Absolutely gorgeous. The place is a little underdeveloped in general, so if you are used to swank this might not be the place. However, I'm sure if you are willing to spend more than I had at the time, you can find a five star place. That being said, I didn't spend much time in the hotels becaues the beaches were amazing.
This place supposedly only gets a few days of rain a year as well.
Assuming Chavez hasn't destroyed this place yet, I would recommend it.