Aust, we went to las vegas as part of a West Coast trip the first time when my son was 8 and my daughter was 15.
I'm really ambivalent about Vegas - in one way I'm really glad we went because it's a fascinating place with the lights and the gimmicks etc in the different casinos. However, I also felt pretty uncomfortable walking the streets with my children, mainly because of the Porn slappers who tried to push stripper brochures into my 8 years olds hands!
There is also the Las Vegas hussle - before you get to the check in desk you are likely to be accosted by an official looking person who turns out to be a time share salesman. They will offer you cheap tickets to attractions etc in return for going to a time share seminar. These guys are also posted at the entrance to a lot of casinos etc. My husband loathes hard sell and he got really sick of them
On that trip we stayed at Paris and I would highly recommend it for your family. We are not really gamblers ( beyond a tip on the Melbourne Cup

, and the advantage of Paris is that you can get to and from your room without having to go through the casino floor. In many other casinos you HAVE to go through the casino floor to get to your room and to restaurants etc, and most of them have pretty strict rules about walking through the casinos with kids. In some it's ok but you have to keep moving all the time , in others you have to be escorted through by a staff member if you have kids with you.
There are some things that appeal to kids, the roller coaster at New York New York etc, some of the other attractions on the strip like M & Ms World, the gondola ride at the Venetian , the FAO Schwartz Toy store in the shops at Ceasars, the Lions and the Rainforest cafe at the MGM Grand etc. You can take them out to see Hoover Dam too. The dancing musical fountains at the Bellagio are fun too.
I'd also recommend going down to Fremont street one evening to see the fantastic overhead light show, my kids loved that.
You can also ( if they like shopping) go to one of the outlet malls, but be warned we found that the Las vages "hussle" was also pretty full on in the malls. They have kiosks every 50 yards or so and the people running them usually try to push hand cream, or almost anything at you. We have them in our malls now but in Vegas there's dozens of them!
After our first trip we did end up going back to Vegas on another trip but only because it was a convenient place to start our tour of Zion and Bryce national parks. We stayed in the Excalibur that time which I had chosen because it was supposed to be more family-friendly, however I thought it was awful and wouldn't recommend it. We should have stayed at the Luxor or Paris.
I wouldn't say "Don't Go" because it really is a jaw-dropping place and maybe it will be your only opportunity to see it ( don't know your circumstances), however just be aware that it really is an adult town and you might feel uncomfortable at times.
Andona