For art, classical music and dance aficionados, Montreal has some great places:
In the Quartier du Musee, I recommend the Musee des Beaux-Arts Montreal (Montreal Fine Arts Museum) at 1384 Sherbrooke West. Some of the spaces were closed to set up new exhibitions but I did enjoy the modern and contemporary art collections. Add it to your must-dos.
I also visited the Musee d’Art Contemporain de Montreal at the Place des Artes 185, Sainte-Catherine Ouest. I was able to see one exhibit but was disappointed that nothing else was open as they were getting ready for the Quebec Triennial. I hope it is open when you visit. The Place des Artes is huge and has venues for the Symphony, Opera, Ballet and Theater. The Maison Symphonique de Montreal is a new 2100 seat venue that opened in September 2011.