Adam, are you Canadian and therefore judging the list from a Canadian point of view (popularity in Canada, influence on Canadian rock music, etc.)? That would explain why a lot of artists are on the list that few people outside Canada have ever heard of. I agree with piper that this is a good list overall.
Yes, I'm from Montreal so that also gives me some perspective on the French Canadian music scene. I tried my best to equally weigh the Canadian point of view (ie Canadian chart performance, Juno Awards etc..) with an International one.
Then I'd say, that's actually a pretty sweet list. Artists from my list you might want to consider: Sarah McLachlan, Justin Bieber, Alannah Myles, Skinny Puppy, Broken Social Scene, Wolf Parade, Jeff Healey, Hot Hot Heat, Caribou (aka Manitoba), Junior Boys, Jane Child, Klaatu, David Foster, The DeFranco Family, Silverstein, Jane Siberry, France Joli, Dream Warriors, Len, Mary Margaret O'Hara, NoMeansNo, Destroyer, Martha Wainwright, Jann Arden, Remy Shand, Honeymoon Suite, Motherlode, Peaches, A.C. Newman