1) Are you able to live comfortably off the salary?
Depends on what you mean by comfortable! I'm definitely living within my means. I just got married and I'm able to pay for rent and help my husband with his college education at the time...and I teach in one of the lowest paying states - Utah! But my job isn't about money, it's about the kids.
2) What are the gratifications of being a teacher?
Lots of notes, the joy of seeing someone learn, and the satisfaction that you are contributing to society and helping someone with your job.
3) What courses are of most importance to take in High School?
Sounds silly, but take lots of technology classes! It is now imperative to have a background in technology to better enable you to teach it to the kids. You really need to have a good ground in a variety of subjects too, because you'll be in charge of teaching them! Take sciences (geology is one I never took and I regret it now), social studies, math, basically all of them!