I've been going to Nathan Phillips Square for years for various events, and of course the iconic NYE bash.
Yes it's a tourist trap, and yes it can get packed but it's still a lot of fun. I was here yesterday for a Pan Am event and while it was packed, there was more seating than I expected, plenty of food concession stands around and it's relatively easy to get to. Do some shopping at the Eaton Centre and then walk over and enjoy the beautiful outdoors. There is skating in the winter but I have yet to go b/c it always seems way too crowded for my liking. Various festivals and events and concerts are held here b/c the space is big.