I'm about to be the weirdo in this group. I'm over half way finished a B.A. in History.
Really, any four year degree will help you. My last boss had a B.A. in Philosophy as well as an A.A.S in Paramedicine. I really think his liberal arts degree has helped separate him from the typical candidate for a supervisors position.
I had nearly finished a degree in theater before I switched to EMS, and my physician mentor during my clinical rotations told me that he wished he had pursued a liberal arts degree in conjunction with his degree in biology. He thought it would help him better deal with people on a more personal and less scientific level.
Really, ANY degree will help you because it will show a prospective employer, should you stay in EMS, that you are able to start and complete something as strenuous as obtaining a four year degree, or higher, should you continue to graduate school.
If you like medicine, look at nursing, or CRNA, or NP, or PA. If you like EMS, get your degree in paramedicine, or emergency management. If you like something else, get a degree in that, as long as you have enough education to fall back on something should your chosen degree plan not work out.
I may never be lucky enough to use my history degree, but I do have my EMS degree to fall back on, so I'm not terribly concerned, and I'm honestly getting the history degree because I want it, not because I need it.