New year is going to be cold mate,moreso if its windy,that's going to cut your options down,some things like the boat tours on the maid of the mist close over winter as its just too cold,if your into skiing or snowshoeing or suchlike that's fine,if it was me coming as a tourist I would come in September,I can tell you a couple of places within 40 minutes of Toronto for salmon and a river two hours from the city that would blow your mind.
Niagara falls is actually three separate falls,the one you see in the tourist pics is horseshoe falls which is spectacular,well worth a visit