Taking the limo is really the only way to go in Vegas, the mere smell of a taxi there can be enough to ruin your trip. Plus, you are already to hurl on your last day in Vegas thanks to extra-curricular activities, do you really want to be in a vomit comet?
Presidential has you covered with their $116 round trip, which is slightly more than your cab ride but worth every penny as they will show up at your baggage carousel and help you take your luggage to their car, that means no 30 minute cab line in 110 degree weather.
These guys seem to have a few issues when getting the billing together, but they work it out and always in your favor. Highly recommended.