No matter which facility you decide on, make your wishes clear in your will and designate a genealogy buddy as your family history executor. You can’t expect a repository to take everything you’ve collected over the decades, so include instructions for that person to weed through your papers to separate what can be pitched from what should stay. Or better yet, get organized now, while you have a say in the matter (our book How to Archive Family Keepsakes and our Organize Your Genealogy Life! CD can help with this).
The Society of American Archivists’ offers more tips in a guide to donating archival materials.