Well Canada is way more liberal when it comes to religion then US, good for you for making right choice - if muslim immigration and reproduction will continue in current rates in 100 years it will be dominant religion here... Calgary already has first muslim mayor in N.America.
And sure you can live in US and be happy atheist - see this data:
A 2006 study at the University of Minnesota showed atheists to be the most distrusted minority among Americans. In the study, sociologists Penny Edgell, Joseph Gerties and Douglas Hartmann conducted a survey of American public opinion on attitudes towards different groups. 40% of respondents characterized atheists as a group that "does not at all agree with my vision of American society", putting atheists well ahead of every other group, with the next highest being Muslims (26%) and homosexuals (23%). When participants were asked whether they agreed with the statement, "I would disapprove if my child wanted to marry a member of this group," atheists again led minorities, with 48% disapproval, followed by Muslims (34%) and African-Americans (27%).[70][71] Joe Foley, co-chairman for Campus Atheists and Secular Humanists, commented on the results, "I know atheists aren't studied that much as a sociological group, but I guess atheists are one of the last groups remaining that it's still socially acceptable to hate."