Everybody has an accent--it's just that the Western North Americans all have a roughly homogenous accent. I can go down to places like Montana and they won't know I'm from Alberta, and even spent two days in Seattle without anyone suspecting I was from elsewhere.
Heck, Nathan Fillion (i.e. the guy who plays Castle, and Malcolm Reynolds from Firefly) who was raised in Edmonton, blends in with the California peeps (don't know their adjective) unless he says "pop" instead of "soda", which isn't an accent thing so much as it is a regional idiosyncrasy.
We (western Canadians) only get flak for saying "about" like "a boat" (not "a BOOT") when talking to the Eastern Americans. New Yorkers in particular seem sensitive to the "a boat" thing.
In other words, it's retarded to try and generalise anyone by their accent. A "Canadian" accent is about as descriptive as a "British" one--and if you ever travel in the UK, you know all it takes to hear a completely different accent is to drive 15 minutes to the next village!