Hi Futuregirl and King Cardinal,
Of course, there is no one solution to every window collision problem. Something that works well for one person may not work well in another situation. We have had many people report excellent results with WindowAlerts (the "frosted decals"), Whispering Windows decals, BirdScreens, CollidEscape film, home-made decals, stencils and Window Wax and variety of other methods.
At home, I use Whispering Windows, WindowAlerts, and stencilled Window Wax, but I have also used black plastic, fine-mesh netting over the windows. You can see a variety of products (http://www.wihumane.org/shop/category.aspx?id=770) and techniques (http://www.wihumane.org/wildlife/wings/treatments.aspx) on our web site.
The American Bird Conservancy has also just released a pamphlet with suggestions for window treatments. That is available here:http://www.abcbirds.org/abcprograms/policy/collisions_flyer.pdf
Regards,
Scott Diehl, Manager
Wisconsin Humane Society, Wildlife Rehabilitation Center
and Wisconsin Night Guardians for Songbirds
Milwaukee, WI