I love the Centurion Lounge before a flight out of Vegas. Being that it is one of the only lounges in Vegas, it really works out when you have to take a red eye and want to have a couple of cocktails and real food before the flight. If you carry a Platinum American Express Card, you are automatically granted access, but if you want to pay to enter, its $50 per person.
The food selection is always fresh and they have plenty of healthy and delicious options. If you are interested in top shelf booze, that's included. If you want to go to the airport and chillout before a flight, then the Amex Centurion Lounge is the spot to go.