THE LANGUAGE
Montreal is the second largest French-speaking city in the world. Its not a Paris knock-off, but the grace and style of the city do give it a European flair. While something like a third of the population is still anglophone (living most in West Island, i.e. the western part of the island on which sits Montreal), everyone serving the public is bilingual. In other words, if you dont speak French, dont worry. Still, you might have fun trying out whatever French you do have, though courteous wait staff will no doubt interject in English to be helpful.
THE CANADIAN DOLLAR
O Canada! Unhappily for Canadian tourists abroad, but happily for Yanks and Brits, the Canadain dollar is at an all time low: $1 Canadian = 63-64 cents American. To compensate, some items are marked up to American-comparable prices, but on the whole, Americans/British will still come out ahead. And Montreal is notably less expensive than Toronto and Vancouver on the whole.
THE GST/TVQ TAX REBATE
Foreigners are eligible for a reimbursement of the federal and Quebec provincial value added tax on purchases other than food. Accomodation therefore qualifies, and most hotels provide GST reimbursement forms. These forms need to be stamped by Canadian customs before leaving the country. This will lower your accomodation fees (not to mention other purchases) even further.