The perfect major: whatever YOU are passionate about and want to major in.
Fortunately, there is no major that will get you into medical school. I say, "fortunately" because premedical students do have to be limited by 'science' majors. Take advantage of this opportunity and major in a filed you are truly passionate about, and a major you can perform well in. Admissions committees will be focusing more on your GPA than your major. More than likely, if you major in something you enjoy, you'll end up doing well, and it will show.
Additionally, for those interested in the non-traditional, science majors, try to tie in your major to healthcare somehow. For example, my friend majored in English & Literature. She took a year off between college and med school by working as the media spokeswoman at a non-profit organization that's researching products to improve healthcare to those living in poverty. Through this job, she has been able to network with many healthcare personnel and physicians, and compete in national competitions for their inventions.
In the end, admissions committees are not looking for what you majored, but how well you did in your chosen major, and what you did with it. Do what you enjoy, and if you're truly passionate, it will all show and pay off!!
P.S. I am still looking for non-trad medical students for my new blog series. If you were a non-trad applicant and want to do a guest post, please comment/email me!