In theory what is it?

Music Education prepares you to be a music teacher in any secondary school.

What is it used for?

same.

What does the major actually entail -- work-wise

A LOT more than you think! Usually several music theory classes, usually participation in weekly private lessons and 1 ensemble(minimum) per semester, recital attendance, sometimes performing a piece on recital, passing proficiency exams on all secondary instruments(including piano), and student teaching.

What kind of jobs do you get with it?

Any music teaching job.

What are the fellow students like (personalitywise) in it?

Very open minded, friendly, creative, unique, and close-knit. In the music department at any college, everyone knows each other and works together.

Common Misconceptions

Everyone thinks music is an easy major and all we have to do is like do marching band or something. But actually, it's one of the most time consuming and demanding majors you could possibly choose. And I'd say it's definitely one of the most competitive.