I won't be building the house. As handy as I am with wood, this is waaaaay beyond my skills. We're currently getting quotes from builders. Looks like it's going to come in around AUD$300k (US$220k). With the cost of the land thrown in, that'll make it a AUD$450k (US$330k) house and land package. Being that this is our first home, it's scaring the crap out of me!
The posts will be galvanised and set directly into the concrete. The concrete will sit just above ground level, enough to stop it from pooling in that spot. The top of the posts then have a steel saddle that the joists sit into and are bolted to. It's generally how things are done in Australia, unless you go for a concrete slab on the ground.
Being on acreage, we don't have town water, so all rain water will be harvested into water tanks. At this stage, we're looking at using two 23,000L (6,000 gallon) tanks. The house is about 39 squares (363sq.metres : 3,900sq.ft.), including deck area.
We'll also be putting down a bore, as the underground water in the area is quite good. That water will be used for gardening, etc.
Finally, we'll be installing a grey water recycling system, that will reuse the water from the showers, baths and hand basins in the toilets. It's amazing just how much fresh water is wasted just flushing a dunny!
Thanks for your input.