Ahh, one last thing - you don't even need a rental car or cab to get from the Airport to your hotel/casino. There's a million shuttles outside of the Airport that cost between $5 and $7 each way, and you can of course get a round trip ticket when you arrive so you don't have to worry about the trip back to the Airport. The times I was there, they had me call the night before I was ready to leave and let them know what time I needed to be picked up.
If you do purchase a round trip fare, be sure to keep your receipt in a safe place where you won't lose it!!! If you lose that, there's no way of proving that you paid for that trip and will have to pay once again...

Some places even give you what looks like a black, $100 casino chip as a 'bus token' to give the driver when you get on the shuttle, which is pretty cool.
Also keep in mind that as with most jobs in Vegas, drivers make very little in hourly wages. So be sure to tip your drivers, no matter if it's a cab driver or shuttle driver, as long as the service was good, of course