Here's an informative article about title insurance.
When my husband and I bought our house, on the advice of our real estate attorney we opted against title insurance. He told us that since the property is registered land, there could be no claim against the title. Not long thereafter I was involved in a case involving title to land and added our lack of title insurance to my list of things to wake up in the middle of the night worrying about. When we refinanced we purchased the insurance. I still don't know whether it's really necessary for registered land, but it sure makes me feel better.