The Palm at Caesers. Binoins Steakhouse used to be the best and most reasonable in town, but with change of ownership don't know now. Binion used the cattle from his Montana ranch and then slowly aged the meat. At one time they didn't even put steak knives on the table. Best I ever ate.
The Steakhouse at Circus is very good indeed. I'd also recommend the Golden Steer on Sahara. Billy Bob's at Sam's Town is also very good, as is Twin Creeks at the Silverton.