We normally fly into Orange County but on our upcoming trip, opted to fly into Long Beach because it's cheaper and it's a direct flight. I love Orange County because it's a nice, smaller airport which is ideal for families. I don't mind larger airports when I travel on business, but I don't like the thought of dealing with LAX with my family.
Will you have a need for a car the entire time you're visiting or will you strictly be spending all of your time at the parks? If you won't be doing anything else but visiting the parks, you can catch a shuttle to the hotel. For a family of 5 (like us), you may want to look into a limo ride. We did this on our last trip and it was $75 each way. It may be considered excessive but the cost wasn't much more than a shuttle/taxi for us and my kids LOVED it. Then if you need a car for a day trip, you can go to Alamo in DTD and rent a car for a day. During our last trip, we did this and it cost us $30 for the day with a free double upgrade coupon. You would be out ~$180 if you did this which is cheaper than the $300 you would otherwise spend and your kids get to ride in the limo!