• theology
• certain industries (such as engineering, chemistry, automotive industries and medical technology)
• the business world, especially where the European market is involved
• literature, culture and philosophy

In light of the wealth of specialized academic literature available in German, practically all reputable PhD programs in the Humanities make German competence an entry requirement. This is especially true of all Theology-based PhD programs.

Need more reasons for studying German? 

http://www.macalester.edu/german/whygerman.html

Or some tools? For vocabular cards try this one: 

http://www.languagequest.com/home/product.php?prodCode=VEGEFC&lang=German

For a very helpful blog with resources try this:

http://ergebung.wordpress.com