I'd say stick with Bardeen and the transistor (if you've read my journal, this should be a surprise to you). There's plenty of arguments here to support the "greatest impact" factor. Besides, as you can already see, it will be DIFFERENT and unusual (just like me!

. Most people think of the usual, standard response, and your instructor will probably expect the same from you and the rest of the students. So doing something unexpected is in itself an advantage. Pick someone and something not many people have either heard about, or paid any attention to, and expose to them the fact that this is such a monumentous discovery that affects ALL of our lives today and yet, hardly anyone have paid attention to it and the persons who made the discovery.
Most people hardly even know that Bardeen is the only person so far to have been awarded the Nobel Prize in physics TWICE!
Zz.