Why do Athiests require 'proof' that God exists?

[Ryft]

Down here in the States there is actually a large number of groups of Christians who think salvation is completely by faith alone (in Christ, of course, not just "faith") on the part of the believer.

Sure, same here. That is sola fide, one of the five solas of the Protestant Reformation. And it is no different from what I said. But ChadWooters was talking about something a little (but significantly) different, namely, "belief alone" being "the only means of salvation." It is true that salvation is by faith alone, meaning that faith is the instrument by which we have access to that salvation procured and secured by Christ's atoning work in his life, death, and resurrection. Christ alone is the means of salvation, and it is through faith that we have access to that salvation (with faith itself being a gift of grace secured by Christ's atoning work).

To them, the faith is completely alone; works comes after as part of sanctification ...

Which, if you go back and read my post, is exactly what I said.

Basically, there's a debate going on between "free grace" salvation and "Lordship" salvation (which would be close to your view) right now.

Aidan W. Tozer: "I present to you a discredited doctrine that divides Christ. It goes like this: ‘Christ is indeed both Savior and Lord; yet a sinner may be saved by accepting him as Savior without yielding to him as Lord.’ The practical outworking of this doctrine is that the evangelist presents, and the seeker accepts, a divided Christ. Now, it seems odd that none of these teachers ever noticed that the only true object of saving faith is none other than Christ himself—not the ‘saviorhood’ of Christ nor the ‘lordship’ of Christ, but Christ himself (1 Tim. 2:5). God does not offer salvation to the one who will believe on one of the offices of Christ, nor is an office of Christ ever presented as an object of faith ... Paul did not tell people to believe on the Savior with the thought that they could later take up the matter of his Lordship and settle it at their own convenience. To Paul there could be no division of offices. Christ must be—and is—Lord, or he will not be the Savior" (emphasis mine).