UK CAA publish a safety review every few years, where they look at various classes of aviation, and their preferred metric is fatalities per million flying hours, which is a fairly reasonable one.
The numbers vary from report to report, but are actually pretty consistent over the last 15 years or so and look something along the lines of:
Airlines - tiny numbers
Certified GA FW, large helicopters: approx 1 fatality per 80,000hrs
Smaller RW, microlights, gliders: 1 fatality per 40-50,000hrs
Homebuilts: 1 per 25,000hrs
Gyroplanes: 1 per 6,000hrs
Or thereabouts.
I agree that helicopters are a heck of a lot of fun, but I defy anybody to show me that a helicopter at £200++/hr gives me more than five times as much fun as I do in a flexwing microlight at £40/hr on the weekends.
G