i have to say the girl scouts of america have affected me most... each year they contribute to the phredgreen's expanding waistline effort...
seriously though... i don't know of any charities that have really hit home for me in any special way, but i'm more of a person that will give of myself (volunteer my time to do work for them) than just dole out money. much more fulfilling as well. i try to do so as often as possible, but due to a lack of many connections within that range of activities, it's been a while. does anyone know where you can look for groups who need help?