Really nice city with lots of nightlife activities during summer (Festival Juste pour rire, Local Gay Pride, etc).
Corner of St-Catherine Street and St-Denis street is the place to be (really hot and fun).
People is really friendly and from all classes.
Visit Park Mont-Royal, Biodome, Jardin Botanique (if you like flowers), Stade Olympique has nothing special but a great view but a bit expensive...) and if you like attractions go to La Ronde (Ile Saint-Helene).
Finish at night by a dinner near the Vieux-Port (old Montréal) or by a hockey game at the Molson Center ;)

If you live in the upper Northeast, Montreal is a great place to drive to with your friends for a quick 4 day weekend. Great nightlife, although the exchange rate takes you nowhere. Take FULL advantage of the Duty Free stores along the borders.

Is montreal!!!! what else you want???

While visiting Montreal, you should buy the transportation card, that they sell at the subway stations. The card costs 3,50CAD and you can charge it daily, weekly or monthly. You can save a lot, specially because the transportation there is good, cover all the city and this card is valid for subways or buses in the town. Great!

One of the best cities in Canada, just about above average pay rate and rent is cheap enough depending on the place. But very rude people there, if they hear you speaking english there, they would get mad and be like "this is a french city, you should be speaking french, if you dont like it, your free to leave the city." as long as you speak french you'll be good there. lot's of things to do in the summer there, LaRonde is an popular Amusement Park in Quebec and is really fun. Very cold winter there though ends around in middle of march. lot's of recreation centers and outdoor pools, Downtown is full fun stuff but also might not be very appropriate for kids.