I heard his essay on NPR one morning on the way to drop the kids off at their (Hebrew) private school, and I was absolutely and completely stunned that someone had summed up exactly what I had in my head so well.
My younger brother and I got into an argument or 3 about the semantics of classifying my beliefs in gods - and it boiled down to this:
Him: Atheism is defined as saying that you know, for sure, that there is no God.
Me: True, and it's damned near impossible to prove that something DOESN'T exist.
Him: Right, so you're more of an agnostic.
Me: Well, I suppose... but I believe that there's a better chance that we'll one day find a purple pegasus having sex with a unicorn. The idea that there is a god out there strikes me as just slightly more laughable than things like transmutation of matter and resurrection... but I suppose that I do not think there's a way we can prove there's no god, so... yeah, agnostic. sure.
I wish that at that point I had been able to sum my beliefs (or, rather, lack of) up nearly as well as Penn did in the above-linked article.
It's not that I actively don't believe in god or gods - it's that I find the entire idea to be ridiculous and dated beyond belief. There's no purpose to the belief - why even worry one way or the other? I live my life with the knowlege that god just has no impact on it. None. Zero. Zip. Nada. The entire discussion is moot - you want to believe in god and jesus and mohammed and whatever other fairy tales you want to believe in, feel free!
I'm confident I'm right... but, just in case, here are the kickers:
1: I live a pretty nice life. I treat my kids right, people around me seem to think I'm not a bad person, and in general I think I'm a positive influence in this world (except for behind the bar, but that's irrelevant here, right?). Almost any religion that believes in a paradise-thing after death is going to put me there.
2: The religions that believe that you MUST be one of them to get to heaven are about as ridiculous as... man, I just can't come up with an analogy for this one. Suffice to say, I don't WANT to believe in their god. He's a ridiculous creation of one-upsmanship and petty jealousy that I would think we, as a culture, are decades past needing.
3: I'm not wrong. Ever.
To sum up, it isn't that I don't believe in god(s) - it's that I believe there is no god. That little difference makes all the rest of the difference in the world.