While overall giving may be growing only slightly, the largest donors in the United States are increasing their gifts by tremendous amounts, according to BusinessWeek’s third annual rankings of the Top 50 U.S. Philanthropists.
For instance, Bill and Melinda Gates donated their entire stock dividend worth $3 billion! That's more than the entire Walton family of Wal-Mart fame have given in their entire lifetimes. The other big gift was from the estate of Susie Buffet (Warren Buffet, Berkshire Hathaway's wife) of $2.5 billion.
For the rundown, go to the article - The Top Givers (registration required).