AMC 24 Yonge & Dundas is in a great location, for a movie theater, being right at Dundas Square.
However, tickets are pricey, and they don't feature the best film selection, but it is a nice theatre. A lot of the better films that are missing from here can be seen at Scotiabank Theatre (a Cineplex facility).
If you go to any AMC, make sure to become an AMC Movie Watcher (soon to convert to the annual membership fee AMC Stubs program) member for an instant discount for movie tickets. Unfortunately, tickets here are not cheaper on any given date.