A good foundation is important in just about everything, from the type of bread one uses for a sandwich to concrete piers. Even in spite of the bad soils we needed to deal with we have a good foundation in place now and will begin framing up walls in the next couple of days.
We had initially planned to use insulated concrete forms (ICF's) for our foundation walls - these are essentially a lightweight formwork that is made from rigid insulation, filled with steel reinforcing and concrete. It is high in insulating R Values, is easy to install and an all around great system. It can be used for whole house construction and many people do just that. We've used it as a foundation wall before on an addition to our current home and like it just swell, spanky.
So of course for this house project - we changed our minds. We needed to save a little money, and talked things over with our builder and mason, "Buck" from Buck-Crete (651-739-3160). We ended up using an 8" reinforced cmu wall with 2" of rigid insulation on each side - giving us the same r-value as the ICF's at a lower cost. And, because the foundation walls are covered up with dirt, well, we didn't feel bad about using concrete blocks. We used Masterblock cmu's - they make a nice product called Enviroblock that contains fly-ash and other recycled content that is a bit friendlier to the environment than typical concrete blocks, as the fly ash replaces some of the portland cement the mix. An added benefit is that the fly-ash (a by -product of burning coal) doesn't end up in the landfill. We save a bit on the extraction of virgin portland cement and eliminate some landfill. So now, when we're down crawling around in our crawl space, wondering where our basement went, we'll have that going for us, which is nice.