Wayne Newton at the Stardust is surprisingly good... No, really.
He earns his title of "Mr. Las Vegas" and will make a believer out of anyone who sees his show. I was dragged along by a date and some friends, but by the time it was over I was glad I'd gone. The last remaining true old school Vegas lounge crooner, had a truly talented backup band & singers, and there's a pleasing "Rat Pack" feel to the show. The music was really solid for what it was.
He also tells some pretty funny dirty jokes, adlibs with the audience smoothly, sends out a bunch of free champagne at random, spends the first 15 minutes of the show drinking audience members' beers and kissing every lady in the audience, and plays guitar, violin, piano, horn, etc. All of them well too. Plus you get a free drink with admission.
We Will Rock You was pretty cool. That's the musical with all the Queen music. It is at Paris.
Wayne Newton wouldn't be a bad choice. He's at the Stardust.
I also saw the Legends in Concert show over at the Imperial Palace. It is a good show for the price. The Prince impersonator is freaky...I think it actually is Prince.
EDIT: thanks for all the other suggestions guys, but bellagio's sounded like a great place to go and i figured i had better book it before i pussed out