The CN tower is a must for any Torontoian. The view of the city from the tower is breathtaking, just try to go on a clear and not cloudy day! Personally, the glass floor is my favourite. While I am afraid of heights, I know the glass is very thick so I just don't think about it. Also If you are going to go, try arriving in the afternoon. It is less busy (most days) and the the city changing from day to night is quite the view!
The CN tower is also great to bring out of town guests. The 360 restaurant has decent food, however, it can get pricy fast.
Overall, the CN tower is always a great time and a crowd pleaser. Just don't forget your camera and bring some extra change to view the binoculars on the top deck!