Mama Luigi's is a great place to go for a casual meal. The staff is very friendly and they have a large selection of items on their menu. Their cheese pizza is one of the best in Las Vegas, plenty of cheese even if you don't order extra cheese on it. Very reasonable Prices and great family meal specials.
Large Pepperoni Pizza + 2 liter of soda for $10 bucks. (requires a coupon, but they print millions of them) You can't beat that!