The Faith of the Founders matters not
Tristero talks about the Faith Of The Founding Fathers and particularly as it relates to the question of whether America is a "Christian Nation".
A lot of advocates of this point of view like to point to evidence of the Christianity of some of the founders as evidence that this nation was founded as a Christian nation. There are plenty of ways to refute this argument, as tristero does in his post. But I think this line of argument is irrelevant. The degree to which the Founding Fathers were Christian has no relationship to the question of whether this country was founded as a "Christian Nation". What matters is the reasons for founding.
Is a Christian Church a Christian Church because Christians built it and go there? No. It is a Christian Church because it was built to advance a Christian perspective on life.
Would we consider any organization of individuals to be Christian simply because a significant number of its members are Christians? Would a school be a "Christian School" simply because most of its teachers were Evangelicals? Would a furniture factory be a "Christian Factory" simply because most of its employees were Seventh Day Adventists? Would a bowling league be a "Christian Bowling League" simply because most of its members were Southern Baptists?
Of course not. Because none of those organizations were created primarily for the advancement of Christian principles. Unless, of course, they were. I could imagine Christians starting a "Bowling for Jesus" league. In which case it would be a "Christian Bowling League". But again, that follows from its foundational purpose, not the faith of its members.
Even if a majority of the Founding Fathers were strong Christians (an iffy proposition at best), that does not preclude them from believing they were creating a secular government on secular principles meant to advance secular goals.
The important question is not who the Founding Fathers were but why they did what they did.