I have been to a few Vegas night clubs and thought they were pretty worthless, small, and lame: Jet, Christian Audiger, Risque.
However, Moon was the greatest nightclub I've ever been to. It's on the top 2 floors of the Palms. More ladies than dudes, amazing views from an outside lounge area, huge dance floor, multiple levels.
I went for my friend's bachelor party and we all had a great time.