wheel - 11:38 pm on May 30, 2011 (gmt 0)
Google.com gives somewhat different results depending on the searcher's location. google.ca will give distinctly different results than google.com for the same location.
Hosting location definitely impacts rankings in google.ca. .ca on a domain, since that requires a canadian entity to own one, must almost certainly be a ranking factor in Google.ca. The hosting location I know is a factor, the .ca domain, I can't believe it isn't one.
Third behind that would be getting lots of links from either other.ca domains, or .com's hosted in Canada. But the first two are gimmes, you should do that.