Canberra suburbs and rentals?

I asked a question a few months ago about Living/ Renting in Canberra. My faily is moving down soon and we are still trying to decide on which suburb to live. We have heard that Weston Creek is a lovely tree lined area with larger older homes and bigger yards??? This is exactly what we want. I like the idea of living in one of the outer suburbs and have heard that Duffy, especially Chapman is a beautiful area to live. Can anyone give me information on theese suburbs? or any similar? Also why are rentals so damn expensive??? Has anyone found it is cheaper to buy a home?