I have always been amazed by this so Christian American habbit to think that there can't be anything possible at all, but be a Christian, accept Jesus in your heart, bla bla bla ...
well, if you think different, then you believe it, so you don't need to tell and explain what you believe at all.
Christians think that you are doomed if you don't believe in God, and in some way want to force the others to do like them, I suppose that they want to gain another chance to get to paradise by saving other poor souls ;o)
Well, let them think what they think, you want change them anyway, never mind to bother them and get them bother you.
When I am asked about this, I just say I don't believe in God, and if the person insists I turn my back and don't listen and give any ground of debating, they have to change their behaviour.
If I am tolerant enough to let others believe things that I personnaly think as stupid and useless, they have to respect my own choice, if not, I am not going to let them ennoy me.
But I don't need their opinion or their acceptance, so I don't speak about my beliefs unless I am asked, and if they are not happy with it, they turn away and go their way.
I think that beliefs is as personal like sex life, everybody has one, but everyone keeps it private. So it is.