I am nominating jXplorer
"JXplorer is an open source ldap browser originally developed by Computer Associates' eTrust Directory development lab. It is a standards compliant general purpose ldap browser that can be used to read and search any ldap directory, or any X500 directory with an ldap interface. It is available for immediate free download under a standard OSI-style open source licence."
I use it frequently at the office to get information from the active directory, so much that other people have requested me to install it for them as it gives them a visibility into the directory that they didn't have before.
EDIT: The website is http://jxplorer.org/
I do not see a donation link for this - pnijjar.
Found http://sourceforge.net/donate/index.php?group_id=55394, FWIW - bswitzer