I go to Montreal at least once every year. They have the highest number of restaurants of any city in north america. Between that competition and a kind of liberate french palate, the food is excellent almost everywhere in the city. Here are some recommendations:
Start by getting a 3-day transit pass (about $17CA). You can get them at Beri-UQAM but if you ask at one of the other metro stations, in my experience, they will just tell you to buy one at Beri-UQAM and let you in free. The pass is good on subway and busses.
St. Louis Square and Prince Arthur - in the early evening ride the Metro to Sherbrooke. Walk through St. Louis park and check out the musicians on the west end; also the painited turrets on the houses beside the park. Then proceed through the pedestrian only blocks of Prince Arthur. There are lots of restaurants here (I have never eaten at any of them because they seem too touristy in a city full of great food) and they are almost all BYOB (meaning wine). A great gelato place is there too.
Marche' Jean Talon - is the green market (and now gourmet market) in the Little Italy section of Montreal. Metro to Jean Talon then ask; the market is within 2 blocks of the stop but is not obvious from the Metro station. Free samples of all the great local produce and yet another great gelato stall. Or if your travels take you closer to Atwater Market go there.
Take the #11 bus to the top of Mount Royale and walk down -- Metro to Mont Royal and then get the #11 bus to the summit. Walk to the Chalet, check out the view of the city, the river and Vermont, then walk down the front of the mountain. The park was designed by Olmstedt (the same guy that did Central Park) but they didn't build it exactly as he planned it. Neat view and neat park anyway. If it is Sunday morning, check-out Tam Tam on the east end of the park by Avenue du Parc.
Walk down St Denis in the evening. Thriving little bars and restos.
Check out Rue Laurier for the more upscale side of town. Patisserie Gascogne features decadent french bakery fare.
If you have kids (and even if you don't), check out Place Jacques Cartier in the old port. Street performers (buskers), artists, and tourists. Cobblestone streets, ancient churches and lots of space that is converted (preserving the stone walls).
For foodies: (as if I haven't listed enough food options) try one of Montreal's better or trendier restaurants. Better = Au Petit Extra
http://www.au-liondor-montreal.com/petitextra/fr/index.asp?section=2 trendy = "Area" (1429 Amherst)in the Village:
http://www.rest-area.qc.ca/ Btw. unlike most of the restaurants in the middle of the island, they don't speak English at Au Petit but they can translate the menu for you if need be.
Go to Ilse St Helene and the Casino. These islands were home to Expo 67 and now are a park in the middle of the river. Gardens, left over pavillions, parkland, etc.
Stay at a Bed and Breakfast - cheaper and you will meet locals and travelers over breakfast.
Some useful links:
A foodie look at Montreal:
http://www.thefoodsection.com/foodsection/movfeast_montreal/index.htmlThe Montreal Mirror (their english language version of ~The Village Voice: events, news, local flavor):
http://www.montrealmirror.com/Site for the International Film fest (8/24 thru 9/4/06) which will include free outdoor screenings:
http://www.ffm-montreal.org/en_index.htmlA list of Bed and Breakfast with links to their sites (the rest of this site is very good also):
http://www.tourisme-montreal.org/B2C/06/accommodation_list.asp?selCategory=H-Gite&selRegion=&selRating=