At risk of sounding like a terrible greedy person there is a significant gain for donating to IRS qualified charities.
I just added $130 (retail value) worth of stuff to my donation box and was curious about the tax savings. So, I went into last years tax records and re-calculated my federal tax savings based on this years donations of $3,000 and the net affect on my tax bill is a savings of $450. Based on this hypothetical scenario, I am earning/saving $.15 on every dollar donated.
"The glory of charitable donations is that you give and receive at the same time."