Disney's cancelation policy is pretty generous, if you're just doing room only I wouldn't bother insuring the hotel stay, just your airline tickets if you're flying.
Do you have a local travel agency that has a Disney Specialist? It might be worth it for you to book the rooms through them since they have insurance companies they deal with regularly. My agent doesn't charge me anything for the service.
You only need trip insurance for the prepaid & non-cancellable portions of your trip. Usually, hotel & rental car reservations can be cancelled without penalty. As always, it is far better to use a credit card (not check or debit card) for deposits. These cc deposits can always be placed in dispute, if there is a problem.
I used www.squaremouth.com to insure my DCL Thanksgiving cruise for 2012. They had great rates and I found the website to be very good when trying to sort through the different types of policies. The main benefit I looked for was a Cancel for Any Reason policy when I was shopping. The policy I did end up buying through this website was a Travel Guard policy.
