Welcome to the Energy Matters Forums MJL
When you say geothermal, do you mean a ground source heat pump, which is often incorrectly referred to as geothermal these days? True geothermal relies on hot rocks very deep down, or shallower high temperature thermal zones in volcanically active areas, such as in NZ.
Ground source heat pumps are very efficient, but also very expensive to set up, as a lot of trenching needs to be done to lay pipework. I think CO2 powered heat pumps would be more economical to install, and they work well in colder climates. Solar hydronic heating is also a good way to heat your house, but if you have extended wet cloudy periods of weather, it will need supplementation with a heat pump, or other other less efficient method such as gas or resistive electric heating.
Wood fires are great if you have access to a cheap supply of wood, and if you have a wetback, you can use that as a source of hydronic heating as well.
The large black water circulating mats that you can put on your roof are quite effective for pool heating, but of course, they dont work so well in cold overcast weather. A heat pump can be used for pool heating, as well as house heating.