The suggestions regarding what to do with genealogical data have been
excellent. In particular the suggestion to donate to more than one
archive is a good one. We don't know where future researchers will live.
Providing the availability of materials to several locations will provide
greater physical access as not every document held by an archive is
available on-line. To build on the idea I suggest creating a catalogue
of your main collection and making that widely available. Finally,
I strongly endorse the American Jewish Archives. I worked there when I
was a student at the Hebrew Union College and can attest to the quality
of the collection and professionalism of the staff.