My dad took me to Toronto and Niagara for an 18th birthday present. I loved it, thought it was beautiful. I went up in the CN Tower (the incredibly tall building with a glass floor) and had a meal in the restaurant at the top at night, which was awesome!
Gotcha, [matt], even though your link isn't working. Glad that you enjoyed your stay in Ontario. The C.N. Tower is amazing and eveyone should try to see Niagara Falls at least once!