Sometimes coming across a good book or three helps you find the language to explain things you already know about yourself. Literature, poised with the power to enlighten inform and change, can also serve the purpose of shining a light on that which you already knew and held dear.
Even my decision to call myself a non-theist (as opposed to using the word atheist) is a deliberate attempt to focus my thoughts and the thoughts of others back on to the meaning of the actual word, so that the taboo's and common misunderstandings of "that other word" are easier to avoid.
I probably owe the clarity of my thinking to three books I've read in recent history, though I preface this to make clear I've since adolescence thought of myself as a non-theist and a secular humanist, long before I ever fully understood what those words and phrases implied.
Lets start with Richard Dawkins. Though I had followed his work by initially reading excerpts of his two books on biology, "The Extended Phenotype" and "The Selfish Gene" (after which I did properly read his books) it was his book "The God Delusion" that helped me understand within myself better how others could believe in absurd things that I could not. Furthermore, that book helped me stop my "fence sitting" on the subject, making me realize that my placations and silence were serving no useful purpose for me or anyone else.
The next author would be Sam Harris. His is an interesting history, that I can perhaps relate to on some level. It appears he reached his state of epiphany after having studied eastern Buddhist practices for the better part of a decade. Though I never formally studied Buddhism myself, I was strongly exposed to it during the years I studied Aikido, so I was aware of just how enlightening this eastern view of the world and our place in it could be trans-formative to ones character. Though Sam wrote several books on the topic, his last full length work "The Moral Landscape" did much to codify my awareness of where he has been suggesting we go with his premises and arguments. He makes a compelling case for rational inquiry into the nature of suffering and its consequences that separates our need to cede this ground to men in pointy hats.
The final and most recent work that has helped me better understand myself and my own thinking in particular is Penn Jillette's latest book "God, No!" Full of wit, and a considerable dose of anecdotes about his crazy life, he distills what it is to be an atheist and humanist into such logical and coherent (and ridiculously simple) terms that it makes me think what this man could have done if he'd been writing books instead of drowning Teller all of these years. :)
All you have to say, to be an atheist, is to answer "I just don't know" to the whole epistemological question. And when you do, it automatically answers whether or not you believe, because you cannot believe if you don't know. These two sentences should get many agnostics (as I once thought I was) off the fence.
Once you realize that the existence of deity is utterly unknowable, it gets such a huge and burdensome question out of the way for you, so you can focus on living your life and figuring out what that is all about. The precious gift of life is itself the reward and the point for me, negating any need to believe in ridiculous and divisive things. And contrary to those who might think otherwise, it is not a path to nihilism, rather it is for me a path towards true enlightened existence.