Had to ask a few younger people than myself on this one. First, they all said the club's are the way to go if 25 years old.

If looking for a bar, for 25 years old, try the Hard Rock, Palms, Brooklyn Bowl in the Quad area and the bars around it.

On certain nights you could check out the Born & Raised bar.

http://www.bornandraisedlv.com/

If looking for a true old-school Vegas Lounge - It is the The Peppermill Restaurant & Fireside Lounge on the strip. All ages hang out at this place.

http://www.yelp.com/biz/the-peppermi...unge-las-vegas

Now if looking for I could give many more options. If traveling alone, at 25 years old - I would stick with the nightclubs. LAS has many great clubs at almost every major hotel/casino.

"Strip clubs" are also everywhere. If you go to one of these, do not let the cab driver "advise" you where to go. They get payoffs up to $100 to bring you to a strip-club. If this is your thing, I can ask which is best lately (things change all the time).

Also, if taking a cab from the airport - make sure not to get tunneled (long haul).

Have a great stay in LAS and I hope the advise I provided helps. Happy travels!