I've mentioned the work of Bob Arens before. His Luxembourg-American Families website is one of the few that addresses Luxembourg-American genealogy in any thorough way. That's why I was so happy to stumble across his personal website this evening.
The website is a bit dated - it's in the old FamilyTree Marker format and hasn't been updated since he started his new site - but it has good bones. The main feature is his personal family tree. If you belong to the Arens family, chances are high that you can find solid information about your own family. Arens has also posted his family's unidentified photos. If you're at all related, take a look!