I second everything Mike said!
NEVER purchase the cruise line insurance - always cheaper and better policies doing through independent companies.
Insuremytrip.com is a good tool, but two things to remember; biggest name is not necessarily best policy because it's the their customer service when a claim is filed that determines how good they are. And secondly, best price may not be the best deal.
Talk to your agent as they usually have companies they work with and feel comfortable with.