If you were trying to choose between 360 at the CN Tower and Canoe, go with Canoe...no contest. Canoe is on the top of TD Bank tower (54th floor) and both the view and food is outstanding. Make sure you check the hours because they may be a little different from what you might expect because it is on top of an office tower. (I think they may not be open for dinner on Saturdays because they rent it out for private functions).
The proprietors of Canoe (Oliver and Bonochini) have a number of other upscale restaurants around town (Jump, Biff's, Auberge du Pommier, Oliver and Bonochini) but I have found that there is a bit of a similarity in the offerings. So, if you try one, you may want to avoid the others. If you like wine, you might want to check out Reds, which is at First Canadian Place at Adelaide between York St. and Bay St. Another top restaurant in town is Bymark, which is in the same building as Canoe, or the owner's other place, North 44, at Yonge St. North of Eglinton Ave.
I would also recommend the dim sum restaurant that an earlier poster mentioned. It is called Lai Wah Heen and it is in the Metropolitan Hotel near City Hall. There are lots of dim sum restaurants in Toronto but Lai Wah Heen is on a totally different level...both in terms of quality of food and price! Look to spend at least $30 to $35 a person (w/o alcohol). If you go, you absolutely have to start your meal with either the seafood hot and sour soup or the crabmeat and corn soup. If you've got room for dessert, they have this amazing sweet cold soup that has tapioca and mango. Also, their mango pudding is the best I've tried. I would also be a great choice for dinner but if you were deciding between dinner and dim sum, go for the dim sum. If you're looking for something that isn't as pricey but still very nice, I would recommend the Dynasty. It is at the top end of the downtown area in the Colonade on Bloor Street West between Bay Street and University Avenue (either the Bay St. or Museum subway stop).
Have fun.