Laura's given some good advice. Basically there's no appreciable difference between physics and astrophysics majors at the undergraduate level (this isn't always true at the PhD level, though). Either physics or astrophysics would be good preparation for a graduate career in either of the two areas. If my advisor were here, he'd probably suggest doing the physics major and taking a few astro courses (this coming from an astrophysicist). Personally I majored in physics as an undergrad, and I never took a single astronomy or astrophysics class. Yet somehow as a grad student, I've stumbled into astrophysics. I admit that my first semester astrophysics course was rather difficult since I've never seen this stuff before. But on the bright side, I did very well in my quantum mechanics and E&M courses, and by some miracle I managed to pass half of my qualifier before my first year. I'd certainly chalk that up to the intensive physics program my undergrad institution has. Whether you major in physics or astronomy, it's very important to get a solid grounding in classical mechanics, E&M, quantum mechanics, and statistical mechanics.
However...you've asked about employment opportunities. In all honesty, physics/astronomy isn't the most employable undergrad degree. If you want a job, you either need to go to grad school, or choose a second major. If you aren't interested in grad school, I'd suggest double majoring in physics (or astro) and engineering. That'll make it a lot easier to get a job should you choose not to go to grad school.