Terrierman has an interesting post about some research in the US, looking into the cost to the public if hunting and trapping didn't exist.
Basically, it would mean 50,000 more injuries amd $3.8bn repair bills per year due to road traffic accidents, additional healthcare costs of $12.45bn p.a. for rabies alone, and $972m in damage to homes by pest species.
If hunters didn't control wildlife for free, it would cost the government up to $9.3bn to control whitetail deer alone!
Fascinating reading - I wonder if anyone's done the equivalent calculations for the UK.