All of those choices could potentially have you working with reptiles, but in extremely different ways. So, you really need to think about how you would enjoy other aspects of the job, your financial goals, and what
kind of work with reptiles you'd like to pursue (notice, I have an interest in field work and so my thoughts emphasize that, while Joyce does lab work and so her emphasis is there), and how long you are willing to go to school.
A wildlife biology major prepares you for a job with a B.S. This may be with fish & wildlife, a park service, a small nature center, etc. These jobs may get you close to the animals and be very rewarding. Not as high paying as the vet job though.
A zoology / biology major (I was a zoology major!

) can also prepare you for those jobs - depending on the elective courses you take. It can also set you on an academic path. If what you want to do is field research of herps, you can either get a job with fish & wildlife (or the like), or go the academic route. The job goal here (after getting a PhD) is a tenure track university position where you have an obligation to teach courses (including herpetology if you're lucky!) and you have to secure funding for your research, but then you get to go out and spend lots of time doing that field research!
I think we'd all agree with Jeanne that exotic vets are badly needed! This is probably the highest paying job working with herps (and birds and small mammals) that you could get. It certainly involves a different kind of work with animals (and their owners), though. Before veterinary school, you'd want to major in biology or zoology - many schools have a pre-vet/pre-med track. Several of my undergrad friends went on to vet school.
Notice that that zoology / biology major is a potential starting point for any of those career choices and offers you some flexibility and more time to make the decision. I would start investigating the zoology / biology and wildlife biology programs at schools you are considering. Not every biology department has a herpetologist anymore - so you will want to make sure that you find a school where someone is actually working with herps (and fish!).
Here are some links that I give my students (who are biology majors):
Careers in Biology
Where do I go with Biology?
Careers in Biological Sciences
Good luck with your search!