Well, the common terminology is:

BS = bulls***
MS = more s***
PhD = piled high and deep

I've got one or more of each, and just about everyone I work with is a PhD as well, so I can say that in my very personal experience, I've found this to be oh, so, true. I'm fairly drowning in the stuff on a daily basis.

To keep to topic, mine are:
BS - Biochemistry & Genetics (one degree, dual major)
MS - Computer Science (done after the Micro PhD)
PhD - Microbiology (actual research was molecular genetics & biochemistry - just happened to be working with microbes)