In Reply to: Re: Religious Doctors No More Likely To Care For Underserved Patients posted by Mr. Don on August 07, 2007 at 06:15:19:
Apparently, Bill Gates is non-religious, if not an outright atheist. So I'd put the Bill & Melinda Gates Foundation in the category you've specified. I googled "atheist philanthropy" and found this blog on the subject:
http://thegreatrealization.wordpress.com/2007/06/05/worlds-largest-philanthropers-atheists/