What are the best Las Vegas coupons in the 2010 American Casino Guide?

Excluding the gambling coupons which coupons are "must use?"
I will be going to Las Vegas for vacation for 3-5 days. Since there are so many Las Vegas coupons in the book I want to make sure I don’t overlook the ones with the best value. For example, I will be sure to use the Rio’s Carnival World Buffet 2-for-1 coupon since it is one of the best buffets in Las Vegas. If there is a coupon in the book for one of the best shows in Las Vegas, that could be part of your answer.