My beliefs (of lack thereof), have come completely from my own head.
I do have a situation quite like you, both my parents are theists (although they don't go to church or pray really or anything like that, but they do believe in God), but my dad is also very intelligent and logical, but he claims to have come to his own conclusions about religion 'from reading the Bible', and is very strong in his belief, but dismisses organized religion.
So that, maybe for a while when I was a bit younger, (and still trying to figure out what I think), that would've had some sort of small influence on my thinking because of WHO it was coming from!
But now, nobody has an influence over me.
I'm an atheist, and that conclusion I have come to on my own, without an external influence, and I don't see anyone changing my mind, (without proof, and well, I don't see that happening anytime soon!)