You could mention the large number of politicians, corporate executives, and other personalities that people look up to on a daily basis who are greek.
I also might mention that you learn things you may otherwise not learn: Robert's Rule of Order, proper etiquette in different situations, Hold an office in an area you may not plan to do in everyday life (for example a Chemistry major may hold the PR office)
There are so many more things, but I think I will leave them to others...