At Tulane, the ACP (Anatomy Certification Program) is the best choice for students who are planning on med school. However, class size is very limited (~15 kids), is competitive to get in to, and requires one be waitlisted at another MD school before they'll consider you. Historically, every student who beats the medical school average in the M1 anatomy class is accepted to Tulane Med the following year.
The Pharmacology M.S. is the second most well-established program and is the one I am doing now. It involves a second year med school course and accessory or supporting graduate work - I really enjoy this type of clinical approach as opposed to the more basic science-centered one, as my undergraduate coursework featured extensive basic science classes. 80% of students are accepted to MD/DO schools within two years of completing the program.
The Anatomy M.S. is a new program that was spun out of ACP. It involves taking the first-year medical courses Anatomy, Histology, and Neuroscience, along with several journal-club type classes. I don't know much about it (it's quite recent), but it involves several medical courses so it will definitely bolster your application.
The non-med M.S. degrees (cell/mol bio & neuroscience) involve a lot more upper-division undergraduate or introductory graduate school courses and are both taught exclusively at the uptown (non-medical) campus. I think they are more flexible in terms of getting students prepared for a variety of career goals, but they are newer and less established in terms of getting people admitted into medical school. Notably, the Cell/Mol bio M.S. costs roughly half of what the other three M.S. programs do, which can be a real positive if you are concerned about debt. They both have good opportunities to incorporate lab research into the curriculum if that's what you're interested in.
If I had to rank the programs in terms of getting someone into med school, I'd say:
ACP > Pharmacology > M.S Anatomy > Cell/Mol Bio > Neuroscience.