Being a local to the Niagara area, there is lots to see on both sides of the border. If your looking for the more tourist type stuff to do, then the Canadian side has tons of places that will love to help you spend your dollars, good places to eat in the Falls area. As Marcarl and Yamaha Par Excellence have mentioned Niagara on the Lake is a pretty spot to spend some time lots of little shops and again some good spots to eat. There are wineries to visit if your into that, if you want some nice drives you can mix that in with doing some visits to the wineries or stopping in the small towns along the Wine Route, again l;ots of neat shops to check out.
just by venturing a little out of the Falls you have more small towns to visit, Marcarl mentioned Fort Erie, there is also Ridgeway, Port Colborne, Virgil, Thorold and a few more each with something different to see. Depending on when you are thinking of coming the region has something going on each weekend of the summer it seems.
On the American side, Niagara Falls NY and Buffalo both have great attractions of their own and some excellent spots to eat and shop.
If you want more detailed info send me a pm and I can look into what is going on in the area when arrive. If your in the mood for a meet and eat that can set up as well.
Wherever you decide you want to go for your visit, it is a great area, ya I am biased because I live here.
Mike