Drai's is THE best after hours spot in Vegas. I always make it a point to visit every time I am in town. The drinks are a little price but hey, it's Vegas what can you expect. The biggest difference in my last few visits is that they made the hip hop room VIP (meaning if your a guy you have to buy a bottle to listen to hip hop). Otherwise it is a great spot with a good crowd considering it will be around 5am when you get there.
p.s. I met Mike Tyson partying there on my last visit