What clubs are the hot spots in Vegas?

I will be going on a trip to Vegas with a bunch of friends this weekend to celebrate their birthdays. I have been to Vegas a few times, but only been to a few smaller clubs. I know there is alot of places to choose from in Sin City. What are the clubs to be at on Friday and Saturday nights? I heard that TAO, Jet, Pure, LAX, and Eve are some of the best clubs in Vegas. But what are the good nights to go? or what other suggestions do you have? If there like clubs in L.A. they are better and pull larger crowds on certain nights of the week. Any help or insight is appreciated=)