1) What is the standard deduction amount?
2) How much "more" (on top of my usual refund) would my tax refund be if I used the standard deduction amount for my personal (material) donations, and if I'm in the 28% tax bracket?
Thanks.

For 2007, the standard deduction is $5,350 for individual.
Charity or donation deduction is available only as itemized deduction. If you itemize your deductions, you will not get the standard deduction. That is you will itemize only when your deductions are more than the standard deduction.
Read this:
Your U.S. Tax Return: Itemized Deductions (http://taxipay.blogspot.com/2008/05/itemized-deductions.html)