What To Do, What To Do

I've run into sort of a dilemma, so I've decided to pose this question to everyone, no matter what your belief may be. Having had a God for most of my life, I didn't realize how much of my life he was a part of, until I stopped believing in him. I was never very religious to begin with, so I never had a problem with taking the lord's name in vain. I actually did it quite often and still do. I still catch myself saying, "Thank God!", which I think has always been more of a saying, than me actually thinking he caused something for me to be thankful for. I've also grown accustomed to people referring to God when they speak to me and never thought anything of it. This is where my dilemma happens. I'm not sure what to say to simple statements like, "We'll pray for you", or when people tell me, "It's in God's hand now".

It strikes me as odd now, that there are no qualms in telling someone you will pray for them, assuming that they want to be prayed for or even believe in prayer, but for me to respond with a "no thank you", makes me feel like the biggest jerk and I'm hesitant to ever do such a thing. While it goes against what I believe in, it is a nice gesture and comes from a good place. Do I say to the person, "thank you, but I don't believe in prayer" and possibly open up a discussion that I really don't feel like having? When I simply smile and say, "Thank you", I feel like I'm conforming myself so as not to offend this person. Would the same respect be given if my belief was that plucking the feathers off of hummingbirds could make good things happen? I mean shit, if you could actually catch one, you're already off to a good start! Would they hold back the fact that they don't believe that? If so, why should I?