Tryst is the hottest nightclub in Vegas. I was there on 1/10/09 and I think it's also the classiest and probably the most expensive in terms of drinks. I think most mixed drinks run around $16 or so over here.
The decor is simply beautiful. The back of the dance floor opens up to the back patio which overlooks a small lake and a waterfall. It's great to walk over to the back and get some fresh air.
The girls are the hottest around. Dress to impress so make sure you not wearing anything dumb like sneakers, baseball caps, etc. The girls will be dressed up (this isn't a jeans / t-shirt kind of place for girls) so guys should look their best.
The crowd is young, hip, and always great for a party. My buddy and I met a group of 17 (yup, that's SEVENTEEN) girls for a bachelorette party and it was freaking nuts partying with them all night long.
Like most of the hot clubs around, it's going to be tough to get in if you're a group of guys (or even a group of girls if you have any guys with you) so do whatever you have to do and get in and join the fun! We got there a little early and stood in line and got in but it took about an hour but it looked like a lot of guys are going to have to wait 2+ hours to get in. I think next time I'll make a few calls or do whatever I need to do to bypass that line because it moves s-l-o-w!