Both of these are in the Plateau, which is "downtown adjacent", but not downtown proper. I had the best latte I've yet drunk in Montreal, though it seems that gourmet pannini pay the bills, at:
Le Lapin Presse
1309 Laurer Est
Montréal, QC H2J 1H4
I'm also turned on to
Caffè In Gamba
5263 Avenue Du Parc
Montreal, QC H2V4G9
As you can tell, we all love Myriade! Try an Eva Solo -- or treat yourself to a siphon: an expensive but pretty cool experience.
Award winning barrista and co-owner Anth pulls some excellent shots (get a single: I think they are better) and is always obsessing about quality.
And they also sell beans (a great gift / souvenir).