Consider alternative forms of donations. Giving time; volunteering locally can mean that you personally see the effects and needs of people. I believe that money going into someone's big bank account is reasonably less provably effective to me than personally seeing the need and attempting to provide for it.

Consider visiting a local shelter and seeing how they are doing. They could probably use an extra $100k; but even if you gave it away; you couldn't see how it was used unless you stayed to watch it be used.