So far so good with finding the fix for Skyrim crashing/rebooting/black screen issue. Approximately eight (8) hours of gameplay with no issues. The current fix (if this lasts 40 hours, I will start calling it a real fix) is:
Disable Core Parking - this is a feature in Windows 7 and newer processors (some i5 and all i7 and higher Intel and recent AMD processors) that powers down unusued cores to save energy. Tom's Hardware and Anandtech and other sites have looked at this and it is generally recommended to turn this feature off. You can find instructions on doing so on the web and I have an earlier post that also has links to disabling it. I am including it here because I know of at least one other user who was hard crashing (black screen/rebooting) and after they disabled Core Parking, no more crashes.
Removing Creative Labs X-Fi Sound Card - For me, disabling Core Parking made the game more stable, but crashes were still observed. After I removed the CL X-Fi sound card and changed to the on-board audio, the crashes (so far) have gone away.
RECOMMENDATION: At this point, if you are having these crashes and have Windows 7, I would disable core parking and see if that works for you. Additionally and regardless of OS version, if you have a dedicated sound card on the PCI-E slots AND have motherboard audio, try removing the sound card and switch to the motherboard audio (for me, this was simply powering down, opening the case, removing the sound card and then closing the case and then powering up).
I believe that the Core Parking plays havoc on the Skyrim processes - but at the very least it lowers performance. As far as the sound card on the PCI-e bus - one observation I had was that my GTX 570 was showing as PCIe x8 instead of PCI x16. This was also fixed after I removed the sound card, so my theory is that the sound card was somehow causing an issue with the PCIe bus. Others have debugged and traced a Creative Labs sound card to show a bus-related issue, so it's entirely possible that the sound card + video card on the same bus is a bad thing, at least for some games (i.e. Skyrim).
Please let me know if this works for you.