1.) I second gene therapy. Huzzah! I am more of a genetics person than an immunology person but both topics fascinate me.
2.) Money, definately. However, it is just a symptom of our misplaced priorities in this world. I don't want to go into politics but I think we could all agree here that scientific research is underfunded and dismissed by people who don't understand it.
3.) C. difficile! I have never studied a more pervasive organism. Study it at your own risk but good luck getting rid of it when you are done.
4.) Favorite: Anything I have never done before. Once I master something I don't have an interest in personally doing it anymore.
Hardest: Plasmid construction. It is a skill I am glad I learned before grad school but I have only recently been able to get a plasmid I made myself to function as a vector.
5.) My proudest accomplishment was one of my first. Genetically engineering some bacteria to smell like popcorn butter based on my own experimental design was a proud day. Maybe not the most practical experiment but it made me a gene therapy believer.