I grew up in Montana. I know a good burger when I sink my teeth into it. Imagine my surprise when the best burger I've ever had the opportunity to experience (at a restaurant,) came from Vegas.
The kobe beef burger is worth every penny. The service is great, Sin City beer is good. There can be a bit of a wait, depending on when you get there, but it's worth it.
Doesn't quite compare to the fresh burgers my dad used to make, but it comes damn close.
If you love burgers, you have to check out the Burger Bar.