G. Mark’s Answer
The cool stuff about biomedical tech or engineering is that it covers a lot of the major engineering disciplines -- electrical, mechanical, chemical -- and merges it with biology study. That pretty much covers all major machines on the planet earth, so it's got to be fascinating. In my experience in medical devices, for example, I've gotten a real kick out of the fact that stuff I designed and built would be used to make someone's life better. When you study a field that has that much reach into society and covers so much of the innovation progress people are accomplishing, it's quite gratifying. And being able to point at someone who is benefitting from your work is, like, the coolest thing I can think of.