The Canon Theatre is great for plays and musicals. Most recently I saw Chitty Chitty Bang Bang and Spring Awakening there. I always look for affordable seats, considering I always take 'opera' appropriate binoculars with me, that way I can see more shows on the cheap. The best way to get tickets to a show is to phone Mirvish Productions directly. The seats I enjoy and are affordable are only available by phone. They are the single seats all they way at the back of the theatre, almost like bar stools. The other are the box seats which are great. The theatre considers them 'obstructed view' due to a row of speakers that are near you, but they only obscure about 1/10 of the stage, and thus are cheap, affordable, and give a great view (not to mention extra leg room, and your own box!)
The theatre has the old world charm, lovely plush seats, great ceiling and common area details. A great theatre to see shows in.