How do you know you are right?

[chumpion]

This has probably been asked before, but humour me...

How do religious people know they have chosen the right religion? I mean, each one is slightly different, and beleive theirs is the one and only true path to heaven to the detriment of all others.

As an atheist, I just can't understand how you could choose one religion and know it is the right one. I mean, what are you going to do if the Catholics were right? Or the Jews? Or the Scientologists? Have you considered looking at all the different strains of Christianity (assuming you are a Christian) before choosing your exact one?

Or have I got it all wrong? Will all Christians go to heaven no matter who they follow?

I guess I am being slightly facecious, but I would honestly like to know.