Invariably I always consider St. Urbain Bagels in Montreal the standard for great tasting "Montreal style" bagels. Thankfully St. Urbain in the Leslieville market holds up to that standard. My last visit I was able to get some yummy-delicious bagels literally hot from the oven. I actually had to separate them in my bag from the cheese I had bought earlier as they were so warm.
I believe there is another place in the Leslieville market that sells Montreal style bagels, which might be worth checking out, but for my money I was quite happy with St. Urbain.