As usual, Jacob Sullum expresses the libertarian viewpoint eloquently:
The number of fatal motorcycle accidents rose in 2007 for the 10th consecutive year, hitting 5,154, 7 percent higher than the 2006 total. [..] Although advocates of helmet laws will be inclined to blame their repeal in several states for the rising motorcycle fatalities, the chief culprit recently seems to be higher gas prices, which have encouraged people to take advantage of motorcycles’ vastly superior fuel efficiency. [..]
Motorcycle riding is inherently dangerous. While wearing a helmet reduces the risk of certain injuries, research suggests the overall impact on fatalities is modest. The unimpressive numbers are one reason motorcyclists have been so successful at defending their right to decide what, if anything, to wear on their heads. “We are the only industrialized country in the world where there is an organized effort to weaken or repeal motorcycle helmet laws,” complains Russ Rader of the Insurance Institute for Highway Safety. Is that a sign of backwardness or a point of pride? [emphasis mine]
How I feel about the last question will be obvious to regular readers of this blog.