As for thanking your guests, I think that once you've given people the option to donate in your honor, I wouldn't necessarily tell folks who give you cash or a coffee pot that you turned around and donated it to a starving child in Africa. You can always donate gifts (or the item they duplicate in your kitchen) to Goodwill or a local organization that provides temporary housing or otherwise helps families in need. If it isn't polite to tell people you regifted their present, it probably isn't nice to tell them you gave it away, either.
Do you have a real-life do-gooding dilemma? Please send it to firstname.lastname@example.org, and Sandy will try to answer it.