I went to Vegas as part of my 7000 mile drive around the states. Apart from a scary overheating moment in the desert in our sh*t Chevy Cavalier it was awesome.
Flights at this time of year are about £300 and accomodation in a nice hotel will be around $120 a night for two people. This is a nice time to go as well as it won't be TOO hot (think hot a Scottish summer

) but will be kinda chilly at night.
It's very tacky in a cool American kind of way. Free drink while you gamble. Plenty to do if you get bored, helicopter ride around the grand canyon, Rent a F355 or Viper etc.
It's one of those things that you absolutely have to do at least once in your life!