God isn't "fun"
Okay, it seems we have some differing opinions here. I am an Orthodox Presbyterian from New Jersey, so I'll give you my take on the subject:
The trouble with a Christian mythos in D&D is that it's nearly impossible to correctly "simulate" God's presence exactly according to the Bible. Since God is infinitely powerful, knows EVERY DETAIL of the past and the future, the DM would not only have to dictate the results of each die roll but be able to read player's minds! The DM would also have to be perfectly pious on top of that.
But let's assume we're not going for strict accuracy(especially where DM piety is concerned). Let's say that Clerics are like the Prophets of the Old Testament and the "Divine Spells" are the miracles. The "domains" able to be granted go as follows:
God: Air, Animal, Fire, Good, Healing, Knowledge, Law, Luck, Plant, Protection, Strength, Sun, Travel, War, Water.
Satan: None, strictly speaking. But if you want to give bad guys a little more "oomph" while not going too left feild: Trickery. Technically, Chaos and Evil cannot be granted because God is more powerful than Satan is and spells called "Magic Circle against Good" or "Dispel Good" are impossible. Note that while Satan is more powerful than all humans and all other angels and demons, God is INFINITELY powerful. While Satan technically never grants "spells" in the D&D sense, he does like people who pretend to have supernatural power for their own greedy ends.
Note that neither grants access to the Death or Magic domains. God has the power over life and death(and there is no such thing as "undeath") and the definition of Magic in D&D is completely different to magic in the Bible(see below). The Destruction domain is not directly granted, but God may use one of the "effects" to strike down evildoers at the right time.
Now according to the Bible, only those who had direct contact with God were granted the ability to perform miracles. They were usually Prophets who are granted their supernatural powers to prove that the messages they delivered were from God. Furthermore, it was rare to have more than one Prophet at a time. Priests were common, of course, but they weren't usually granted the ability to do miracles. (EDIT: Interestingly, although all Prophets were Lawful Good, alignment violation usually resulted in a deferred punishment rather than a loss of power. For example, Moses was commanded to speak to a stone instead of striking it(he was commaned earlier to strike a different stone) so that water would flow from it. Instead, Moses struck it. Water still flowed and God did not remove any of his power or approval from Moses, but instead Moses was severely rebuked and not allowed to enter the Promised Land, only to view it from a distance before he died. In another example, God promised a king(I forget who) that he would not die for twenty years, effectively making him invicible. This miracle was abused, so the king's life was ended soon after the twenty years ended.)
(EDIT: One more thing: Although God never had a Preistess serve him, there were some Prophetesses. They were extremely few in number, but they did exist. Also note that while it was extremely rare, sometimes there was more than one Prophet at the same time.)
Note that the biblical definition of magic is completely different to the D&D definition of magic. They are simply not the same thing. (The ignorant misconception that they are the same thing is what led to the trouble with B.A.D.D. (Bothered About Dungeons & Dragons) back in the 80s.) Necromancy and Sorcery in the Bible are always evil acts and never have a more powerful effect than the equivalent of a 1st level D&D spell. Divination is also usually an evil act except if God commands it(God used the casting of lots in a few miracles to show that he had power over "random" events and fate itself, but USUALLY it is inappropriate). These things are more evil than "ordinary" sin (lying, adultery, murder, idol worship) and it is very rare for those who perform such acts to repent. Contrary to common knowledge, the knowledge of how to perform such acts is not considered evil (Daniel was trained as an Astrologer), only actually performing them. (EDIT: the reason for this is that usually these actions involve calling or consulting with demons. I just thought I'd make this clear.)
(EDIT: Also note that there are no "magic" items. demons never created anything so they obviously could not imbue objects with supernatural power. God did make a lot of what in D&D terms could be considered "Artifacts": Aaron's staff that could change into a very strong and agressive snake, the Ark of the Covenant(yes, THAT Ark), Elijah(or was it Elishah?)'s robes that could part the rivers... Of course all these things could only be used to do God's will.)
Nearly all of the spellcasting classes (As defined by D&D) do not exist, though Clerics = Prophets isn't TOO big of a stretch. Wizards and Sorcerers are 1st level at best(and always evil, though they may be anything on the Ethical alignment axis) or are actually Experts(of various alignments but usually evil) who specialise in alchemy, astrology and magic tricks. Most D&D spells aren't available. On the other hand, most monsters don't exist either.
Most things outside of the animal appendix don't exist with the exception of some Beasts (some dinosaurs are in the Bible) and Vermin. Outsiders are EXTREMELY rare except in visions(angels) or posessions(demons). There are one or two instances of what could be called Elementals at a stretch, but Aberrations, Constructs, Dragons(A dragon image is used to represent Satan in some visions), Fey, Humanoids(except for humans, of course), Monstrous Humanoids, Undead, and so on do not exist. I think some Jews believe that there was something called a Golem(a Clay Golem to be precise), but I think including that would be a stretch because it doesn't appear in scripture.
Angels are always Lawful Good. Demons(Devils are the same thing) are always Chaotic Evil. Furthermore, the only real difference between them is who they work for: God or Satan. Fallen angels(demons) have similar power that those still loyal to God do, they just use their power for evil. Demons cannot harm those who have Faith in God. Demons cannot and will not repent. The Bible is vague on the limits of the power of angels and demons, but many demons have been restricted or imprisoned in some way. Beyond that, the Bible is mostly (deliberately) vague about what goes on in the supernatural realms.
That's pretty much it. See? The Biblical mythos is interesting but not nearly as much "fun" as D&D in a gaming sense.