Smile Forever/Colin Street Dental in West Perth is excellent. They do twilight sedation, and don't sit you in the dentists' chair until you absolutely HAVE to sit in it - so it's very relaxing and stress free.
I have been going to Peter Ryan in the City for many, many years. He is so cheap, it is almost ridiculous, and every year I have a checkup, and get all of the cost back from my health fund.
He is definitely not the sort of dentist who continually finds things to do as in about 20 years of going to him, I think I have only had about 2 fillings whereas before they were always finding teeth to fill, and ways to get me back.