What to do in Las Vegas?

I'm going to Las Vegas in December and looking for some advice on what to do and how to make the most of my time there. I'm 26, male, never been there before, and staying for 4 nights. What would be the best club/place to go to party? (aka where are all the hot girls at? haha) Where to go for gambling? I'm probably only going to try a little blackjack and maybe bet on some sporting events. I'd appreciate any advice or ideas on where the main places are to go to. Thanks!