The town isn't much to look at. The falls is nice to look at for 10 minutes. There a million touristy things to do there, depending on what you like to do. Lots of nice hotels, with views of the falls, and lots of deals to be had on the various groupon and knockoff sites. If you like waterparks, the largest Great Wolf Lodge is here, as is the rooftop Fallsview Waterpark right near the Rainbow Bridge.
Outside of the city, Niagara On The Lake is a pretty town and lots of wineries. The Welland Canal is interesting if you like to see ships up close. Lock 7 in Thorold has a visitor centre and you can talk to the crew as their ship goes by. It doesn't have the PR or exotic location of the Panama Canal but it's a pretty interesting place if you catch the right ships, which will likely be iron ore haulers.