I second Progressive. I've had 2 bikes insured by them, and their rates were well below State Farm.
The reason that State Farm couldn't be competative is that they could not break out collision and comprehensive as ala' carte items. Progressive can.
I pay $137 a year for comprehensive only, $1,000 coverage on "factory-authorized" accessories, and a $100 deductible. Like you, I am only interested in coverage in the event of fire or theft. I know I will crash, and most fixes will (hopefully) be less than a $100.
The kicker is that $75 of the $137 premium is for the MCCA - Michigan Catastrophic Claims Association fund. This fund covers "those injured in accidents that do not involve a motorcycle". What a rip! :scream: I am paying over half of my premium to a fund that I can never potentially benefit from.