When you're at the (Canadian) Falls a must do is the 'table-rock' tour.
In the building where the souvenir-shop is located there is an elevator taking you down to the base of the Falls.
Everybody gets a raincoat (poncho) and you'll have to walk through a passageway to a big balcony kind of platform.
Now you're standing right under the Falls (which is the most spectacular, must see.. view besides taking a boat tour with the 'maid of the mist')
Traveling downstream along the Niagara river is probably one of the most scenic tours in all of Southern Ontario.
You can take a gondola tour at the 'whirlpool' (a big, sudden 45 degree turn of the river) or visit the botanical gardens with a butterfly conservation area (house).
Following that road for about 30 minutes, it will lead you to 'Niagara on the Lake'.
This is a very pretty little town with nice cafe's, horse carriage rides and more.
Niagara on the Lake used to be the capital of Upper Canada a long time ago.
P.S. Niagara is pronounced like 'Viagra', just with an N instead of the V
Marc