You can't really go wrong when it comes to clubs, girls are everywhere. Just a matter of what kinda music you like, if you care.
Check this site out to get on guest lists for free, I tried it last time I was there and hit up Pure at Ceasars Palace on a Tuesday, it was crackin.
Free Vegas Club Passes
Out of that list, Tryst is tight, they got a big indoor waterfall, Voodoo is a rooftop club at the Rio which is cool too...Cathouse at Luxor is a no-dresscode spot and you can get cheaper bottle service and hookah there. Just a few to choose from. Happy hunting.