Burgers are still one of the rages.
My burger choice would be In N Out. Not because they have the best burger. It's a good, but fast-food burger, but it's worth the money. But that's not what you're looking for, so scratch In N Out.
I haven't had many. But I had BLT Burger (note, Laurent Tourondel is no longer part of this -- he sold out after I ate there to a food corporation). Nothing special about it. And I spent something like $15 on just the burger. I had one of their specialty shakes. I had the onion rings. The food was good. Not great. Much better than fast food or a Dennys or the like. But if I were to spend almost $30, I could do much better in Vegas at a variety of foods.
The BLT Burger has beget other burger places with initials. There's one at Harrah's (KGB), one at Red Rock (LBS).
Holsteins in Cosmo has gotten decent reviews but is overpriced -- they do have a great milkshake menu.
The Burger Bar in Mandalay Bay might be your best bet for the burger. Hubert Keller knows what he's doing. However, Burger Bar doesn't have the exotic shakes when I checked.
Note: my favorite Nevada burger place is the Awful Awful at the Nugget in Reno (not Sparks). $7. Great burger.