In Boulder City, NV, the best burger in town (and maybe the best burger I've ever had) is at The Dillinger.
We ordered the signature burger, the Dillinger, which is a bacon cheeseburger that is topped with a very moist beef brisket. The burgers are huge (1/2 lb.), but delicious and even when cooked to medium well remain moist and juicy. It's clear someone in the kitchen knows their way around a burger and a grill. The Dillinger is then topped with cheese, strips of bacon, and a nice sized portion of some of the best beef brisket I have ever tasted.
The Bugsy, similar to the Dillinger, has cheese and bacon, and then has a healthy portion of sautéed onions on top. The onions were surprisingly sweet onions that were cooked to a soft state and paired wonderfully with the burger base.
We had read on FourSquare to try the onion rings. The burgers come with french fries with the option to upgrade to onion rings. The onion rings were phenomenal. The onions were cooked through while the outside was crispy and crunchy.
The service was friendly, although the restaurant was busy for a Saturday late afternoon.