I think best Holiday is Vegas fro adults. I mena it was like a lingerie show. IF you have open minded GF or wife, you will be find. Ton's of costume prizes etc.. For the cost it is great. Of course New Year is better in Vegas...but rooms expensive. Now If you are not into clubbing, dressing up or having fun...then Halloween is not for you.
https://www.halloweenball.com/2013-event-info/ link to the ball. The wife and I went 3 years ago age range from 21 to over 80 it was a blast. I Like Fremont better than the strip for people watching on Halloween. We got married in Vegas dresses in full costume 8 years ago on Halloween