I happen to entertain a Deistic belief which, from all I've heard and read (not just here and at TAM4, but all the years I've been on the forum) doesn't seem to differ very much from Hal's. I do not claim to speak for Hal, nor do I claim that my statements explain his position exactly; however, being that I believe in nearly the same things, I might be able to lend some insight.
First, I think JamesDillon's characterization is flawed at the beginning. Like myself, I believe Hal was not an atheist/agnostic at the beginning; rather, he may have "accepted" the existence of a god (perhaps even a personal one) in a very general way - for example, he may not have gone to church often or at all (I didn't), he may not have spent time pondering religious matters (I didn't), and he may have made decisions based on a moral code which perhaps was taught to him via religion, but not essentially connected (i.e., Hal did "the Right Thing" because it was the Right Thing, not because he feared going to hell). But perhaps he considered it a general given that God existed. This is why he describes praying during his time of extreme calamity. It's not that the calamity caused him to suddenly believe in a god, it's that he reacted with prayer because that's "what you're supposed to do when you're in trouble", according to the background religious belief set. He mentioned very specifically that he never really thought it would work.
I'm not sure I could guess as to the exact process of Hal's transforming from this quasi-Christianity to the Deism he now entertains. The way it happened with me, it simply occurred to me, or started occurring to me, that there was something wrong with the way things were versus the idea of God I'd been believing. As these essential "truths" I had grown to believe in began to look not as solid, I turned to an alternative way of viewing reality which had been proven, in my eyes, to work all the time - science. Still, I had grown to fancy the idea of a God, and for certain emotional reasons which I won't go into, I was unwilling to abandon that idea. So, I proceeded with the philisophical assumption that a god in some form or other existed.
When I applied the Scientific Method to God, I discovered that although God wouldn't disappear completely, nor would he ultimately be shown to exist for certain, I could get a pretty good idea of what God was not. For example, he does not seem to interfere in the day-to-day operation of the Universe. We can tell this because we can find nothing within it that can't be explained naturally. We can tell that, therefore, God doesn't favor or speak to specific people; he doesn't perform magic tricks to get people to believe in him, and so on. If we were to apply reason to God (again, assuming he exists), we would determine that he (He?) should not delight in the torture of his creation, that he would not want an animal with such a capacity for thought and reason to voluntarily abandon those faculties simply to adore him, that he would not care whether an individual "believes" in him or not. Certainly, any reasonable "God" would not rely on such faulty mediums as texts and word of mouth to reveal himself.
And so on it went. I started with the Christian concept of God and used science and reason to peel back the various layers until I arrived at the core - essentially, a philisophical construct which created the Universe and then left it alone, to hang like a painting, for instance, in his chamber to admire. I don't know whether "God" really is a "he" or she, or even if this god is sentient. For all intents and purposes, my vague, nebulous notion of a god results in a physical universe which differs in no way with a universe in which there is no god. That's why I get along with atheists so well.
So why do I accept this god? Why not just leave him off and have done with it? Because, quite simply, I have "scienced" God into a concept that no longer has any implications in the physical world, and therefore into a purely philisophical concept (as opposed to theistic concepts, which rely on an interfering god which has or should have scientific antecedents). In philisophy, the rules of naturalism no longer apply. Sure, you can insist upon using some sort of logical positivistic viewpoint - but my emotional desire for the existence of a god, in this wonderful land of philosophy, is an equally valid argument. If that emotional desire were not there, I would probably be an atheist. Perhaps, if or when that emotional desire disappears, I will be an atheist. Perhaps, so will Hal. And yes, I know it's difficult to understand how one could sustain an emotional need for something that is pretty similar to nothing at all. But I'm not very articulate.
So, I don't know if there's an afterlife, or if God has emotions or is even intelligent. It would be nice there was an afterlife, for instance, but I can't say for sure without feeling uncomfortable. And these are only my own opinions, of course - I don't typically explain the deist position to people unless they ask; indeed, the only reason I'm even mentioning it here is because I think it will help people understand. I hope it will, anyway. Yes, deists are very difficult to argue with about religion, because the generic deist concept of "God" is so nebulous, and you're all used to debating the Pat Robertsons of the world. Sorry to disappoint...
Meanwhile, of course a skeptic doesn't have to be an atheist. I tend to agree with those who say skepticism is a method, not a category. It's as if some feel that, to enter the "club", one must adopt a creed which simultaneously renounces a certain set of beliefs. This idea is bad for a few reasons - primarily because it doesn't allow for a pathway to "Ultimate Skepticism". It doesn't suffer those who may need to take baby-steps, slowly giving up this belief or that belief as they encounter the need to examine each. And it doesn't allow for the fact that anybody - me, Hal, kittynh, and the various other "believers" - may become atheists at any moment, but just haven't gotten there yet. The same may be true of anyone, of course, but how far along have we gotten? We join the fight and wade into the very center of the battle against UFOlogy, homeopathy, psychic frauds, and religious and scientific charlatanry, only to come home at the end of the day while the Hornbecks we've been fighting with turn on us and say "You hypocrite! You fraud!" And we still press on. It’s our fight too; it would be a shame to leave us out of it over some semantic minutae.