I checked out the Lights of the World with my 4 year old daughter last weekend.
IT IS NOT WORTH THE MONEY!!!!
The display of lights were beautiful and interesting, but it definitely was NOT worth the $40 that I paid for the 2 of us to go. On top of that, you also have to pay $10 to park!
If you don't see any of the shows (which we didn't) and don't ride the rides (more on that in a bit) and don't eat any food, you can see all the lights in about 45-60 minutes. The food was typical fair food and the rides were rather pathetic. There are only 4 rides that my little one was able to ride and those rides were broken (none went up and down, so they just went around in a circle.) Also, make sure you bring cash. Some of the vendors and ride tickets can only be purchased with cash. There's ATMs around, but do you really want to pay $5 to withdraw your own money?!?!
I WOULD NOT RECOMMEND THIS.