I haven't been to Niagara Falls in a few years but I don't live that far away. The American side of the Falls is considered the more natural side. If you head to Goat Island you will be right by the water. The Niagara Power Authority is fairly close and has a free, updated information center. There is a small aquarium in the city. There is also a new casino that has very good concerts and shows. Most companies have left the area so the American side is slightly depressed.
The Canadian side built a few casinos too and development really took off. I believe there is an I-MAX theatre and some kind of Amazon Rainforest Bird Walk.
The Canadian side actually has the better view but you can get right by the water on the American side. You can park your car and walk over the Rainbow Bridge (it's a long way down

from the U.S. to Canada. In Canada, the Cave of the Winds takes you to the base of the Falls - it's cool.
They put lights on the Falls at night and it's very pretty.
If you plan to visit the Canadian side BE PREPARED WITH THE CORRECT DOCUMENTATION. The officials on both sides are very tough w/documentation - even for children.
P.S. Like most "natives" I have never been on the "Maid of the Mist". (Isn't that always the way w/local attractions?) But it's still going strong and everyone seems to like it.
Enjoy!