Palms is the best for younger people, hands down.
They have 4 amazing clubs, Rain, Moon, Ghost Bar, and Playboy Club. Moon and Rain are the best, and both usually have pretty high caliber DJ's spinning. Try to check out both.
Like BONEZ said, your going to have the most fun if you can put up for a table, because you won't wait in line, and you won't have any problems with women flocking to you. Fortunately I've always had table service when I'm there, and it beats the pants off of waiting in line, walking around aimlessly, and having to pick up the woman version of table scraps.
Best Buffet? The Wynn, high quality food and a bigger selection than you could ever comprehend.
Vegas also has great shows if that's your thing, if you check out any of the Circ de Soleil you will be more than blown away. Check with your concierge for ticket deals.
Checking out the Spearmint Rhino is also a must, just stumble into a cab when your rolling out of Moon or Rain at 5am in the morning and head straight there. It is the perfect way to top off an amazing night, if you haven't already stumbled back to your room with some dime piece.
Seriously though, it's Vegas, so if you stay in the mindset of having an amazing time, it's going to happen. Talk to whoever you want, pretend that your whoever you want, and spend as little time as you can in your hotel room.