There were a number of factors that led me to atheism, but I want to talk specifically about the people who helped me to make that choice. None of them were family or friends; they were bloggers, youtubers, and musicians. I'm not sure I remember the exact timeline, but I have enough details to explain. It all started with the Skeptic's Dictionary and significant free time at work. I read the whole thing, from A to Z. Somewhere in there I found a link that led me either directly or indirectly to my first inspiration Pharyngula, which I started to read regularly.
PZ Myers was an inspiration in that he was the first atheist I found whose writing I liked. Unlike some of the other writers with whom I knew atheism was involved, PZ was a big softie. I liked his writing style and how approachable he seemed. I learned from him that I could be firmly against religion while still not being an asshole. Through PZ I learned about all of the other atheists to follow.
Greydon Square was my first black atheist and arguably one of the most convincing atheists as well. I found out about him through comments somewhere, and after looking into his music I downloaded The Kardashev Scale. I was hooked immediately. The passion and anger on the album were compelling. I've been following him ever since.
Greta Christina's blog, specifically her atheists and anger post really got to me. She made her point eloquently and forcefully. I couldn't argue with her on almost any point, and I was amazed at the sheer length of her article. She is one of the calmest and wisest voices in the atheist world but she can get just as angry as anyone else.
Last and certainly not least, AronRa and his Foundational Falsehoods of Creationism were a huge influence. I don't know what it is about AronRa, but his voice is so compelling and what he says so calmly hits like a ton of bricks. He doesn't need to talk often, but when he does it's very often worth saying.
If you want my four horsemen, these are them. Or, more accurately, these are the correct four horsemen of the apocalypse.