I know I'm a newbie, and I didn't read the whole thread, but I actually researched this a week ago (slow day at work).
Of course it depends on your state (or possibly local) government, but in CA buying and living in a home in an area that can be reasonably expected to get hit with golf balls is considered an "assumption of the risk," and despite all the signs on the golf course, the golfer is NOT held responsible for property or even personal damage. I can find the specific cases again, if anyone in CA is interested.
That said, I've split the cost of a window with the homeowner (it was actually an iron shot, off a branch, through a window), because it's the right thing to do. I'd do it again, even knowing that I wouldn't be legally obligated.