The best store-bought lightning protection system may be the guarantee it's sold with...
http://www.dehn-usa.com/dehn-Application-Guides-pubcid1.html <-- their Lightning Protection Guide is a good read even if it is a showcase for 'their' components and worth the 16 megabyte download.
http://lecglobal.com/solutions/lightning/protection/ <-- another form of protection... Dissipation to prevent a static charge 'leader' from getting energetic enough to make the jump to full conduction.
The average lightning strike is 15,000-25,000 Amps so you want multiple methods in multiple areas to keep the direct strike out of your life.
Without spending as much for lightning protection as you did for the tower or wind turbine itself the best you can hope for is avoiding damage from a near-miss that saturates metal for hundreds of feet in all directions with high voltage surges. This has been posted on many times, use the google search function to see some of the best this group can come up with...(be sure to use the " -ungrounded " search term so Fieldlines user Ungrounded lightning Rod's posts don't clog the results (no offense ULR))
