I'm glad you're thinking about this now, instead of at the last minute, JR. You still have some time before you formally declare, so it bodes well for you that you're pondering this in advance. I think it's a sound suggestion that you take a course or two in the discipline you're considering, or at least audit a class for awhile. Also, make some acquaintances among upperclassmen in that department and gain their perspectives. You may want to make an appointment to talk with an instructor or advisor in that department too, just to see what he/she says. Go to the appointment armed with questions, especially about your potential long-term course of study.

Only you can come to the right decision in this situation, after careful thought. Pursue the discipline about which you feel most passionate; if you play your cards right, you'll be able to make a decent living at either, regardless of the job market.

Good luck!