I just wanted everyone to know that I found the best insulation for below grade. I have been picking away at finishing my basement since I bought my spec house new in 2002. It is a 1700 sq ft ranch with full 12 course basement. It has exterior below grade insulation, about 1' thick rigid fiberglass. But there are 3 or 4 courses of block above grade that are uninsulated and because of that, the basement always felt cold.
So I did as much research as I could, and if you do enough you find out about moisture problems and mold. I found the solution- expanding foam. The typical application is for older homes with little to no wall insulation, but they do it for basement block too. They drilled a 5/8" hole in each column of block and squirted this liquid stuff in there. It expands to fill all the cavity and turns into styrofoam. Then another person comes around and mortars the holes, you never even know they were there!
They also did my garage walls, so in that case they removed a section of siding to get to the cavity.
Here is a link to the company: http://www.polymaster.com/retro.html
I think there are other companies than just this one that do the same thing, but these guys were the closest.
I have saved a ton already on my gas bill and there is no longer that feeling of coldness when you go down there.
Anyone else tried this stuff?