We also heat by oil, which I think is the most commen thing in our area. When the oil prices went sky high we looked into the wooden pellets, but found out although they're produced locally, or we could also by them in Germany as we're close to the boarder (what we do for wood for our stove that we use in this kind of weather) they are still expensive. We're now looking into a solar panels. There are 3 main systems though - just warm water, water and heating, or also electricity. Of course the more you want, the more you pay and it does take a 'few'
years to pay out - therefore a real longterm investment.
A note to ordering oil as a group - most companies ask for an extra fee for each house they deliver to -so it really only makes sense when you happen to have lots of households that need oil at the same time (never works out for us) so that you can order a very large amount.
Regarding buying, renting or rent-buy option. That really depends on how your finances look, how long you're planning to stay in CH, and what area you're living in. I live out in the country in Aargau, and the property market is very slow here. I can imagine that in the cities it's not as bad, but still not as fast as in the UK. Rent-buy option might be a good idea as you normaly have the chance to end the contract, maybe you'll decide Switzerland isn't the place for you - and then you'll only have paid 'rent', and if you stay you've already paid some money towards your house...