Sorry insulator, I'm not nitpicking your spelling, I just want anyone who searches to get the right info. BTW I agree with everything you have said.
Condensation is just one part of the problem. Sometimes there is a high water table, or poor drainage that can't reasonably be altered. In such cases you can channel the water to a sump pump, but you will still have wet ground. If you cover the ground (running up the foundation wall) with pinhole free poly such as Tu-Tuf and tape the joints, you will isolate the house from the water. It also isolates the house to an extent from soil gasses that can enter the house due to the fact that crawlspaces and basements are often souces of makeup air as heated air escapes.
With the vents closed and the foundation insulated, I believe that the crawlspace will stay plenty warm in all but the coldest climates, so putting a warm air register there would probably only benefit extreme cases. This is not an academic exercise, it is done all the time; it is the approach favored by and practiced by the building science community. As far as expense, I don't see that the cost of poly and foam board is prohibitive. Home Energy mag. has done articles in the past on this, most of their issues are on-line at www.homeenergy.org.