In grad school it would have been the seminar on Density Functional Theory. (ex. how to do detailed computer simulations of the properties of materials.)<p>As an undergrad (I studied physics and math and went on to do a PhD in condensed matter theory) I would like to have taken some more CS. I traded CS 101 for a comparative programming languages class and also took one credit courses in C and TeX from the illustrious John Shipman. A compilers class would have been nice too.
Im happy with what i took, but i wish i took more time. Dont course overload, especially in classes that lay the foundation for advanced coursework (like linear algebra and stats)