How much are your frequent flyer miles worth?

My wife's Grandmother had a stroke this weekend, so after just starting to settle down in Boston, we're off to SF this week again. I spent some time trying to figure out whether or not to use the FF miles, especially given the bereavement fares the airlines have. I found this interesting article on how to value your FF miles:

http://www.usatoday.com/travel/columnist/brancatelli/2005-02-28-brancatelli_x.htm