I was indoctrinated into religion by my parents and the various adults at the different churches we attended. For years, they were the biggest influence on me and my views of religion, when I didn't even have the critical faculties to understand what it was I was "believing". I was told God existed as a fact, and that not believing could lead to burning in hell for eternity, and that the Devil was real, etc. etc. Pretty scary stuff to a kid.
Then, the next biggest influence wasn't a "who" so much as a "what". I began noticing that my belief system made no sense on many different levels, but I didn't want to delve or think any further, mainly out of fear of hell and burning for eternity, but also out of fear of what it would mean socially if I were to reject a belief. So, for many years while I was a teenager and even in the beginning of college, my views of religion were based on fear.
Over time, especially once I was out of the house and on my own, the fear of social ostracization faded, and the fear of hell slowly faded, I began to explore the parts of my belief that had never made much sense. There was no one person that influenced me at this time, there were multitudes. Various books I read, various atheist friends (who I had never known of before) I had, various articles, even some discussion from here on DU, and lots of other internet sources, slowly, very slowly chipped away at what had been a lifelong comfort and also source of fear for me.
Now, what influences me the most when it comes to my views of religion, or many other topics, is skepticism. I try to apply it in all areas of my life.