Each of these hotels offer qualities that can help create a family friendly Las Vegas vacation. Generally, I would stay away from Downtown Las Vegas Hotels for kids as there is much less to entertain the children. Remember, Las Vegas is an adult playground so you might come in contact with smokers, drinkers and scantily clad party goers. If you can deal with that you should have a great time.
Monte Carlo Hotel and Casino has a great pool for kids and fast food restaurants right near the elevators. The rooms are spacious enough to cram in the kids and not step on too many toys. Great location across from the showcase mall and Gameworks.
You'll be pleased with the pool area because it has a lazy river, a small wave pool and a couple of smaller pools that allow you to spread out and expand the fun factor. There is also a spot with sand where a volleyball court is set up.
Food options include a decent food court with pizza and a McDonald's as well as the Pub that is usually kid friendly during the afternoon hours. d.Vino has moderately priced Italian food and some good lunch specials.
Location: The Monte Carlo is between the New York/New York Hotel and CityCenter so you get plenty of options for entertainment and food. The kids will enjoy the attractions at NY/NY and Excalibur and they are all in walking distance. If you want to spend a little more money and have some space for the entire family consider Hotel 32 at the Monte Carlo.