+(1*2)^1k 😀
Honestly, though, do what you're most interested in. This will allow you to put in the 50+ hours per week (in tough weeks) to do well. Moreover, doing what you really like in UG will allow you to do the extracurriculars, research, and other perks that will make you a well-rounded applicant.
EDIT: As a corollary, focusing solely on GPA "fluffing" will make you miserable. You need to enjoy what you'll be doing, or you'll have a grueling UG.
Also, while most schools do not put any numerical weight to a particular major, they will be impressed (or lack thereof) of your workload. If you major in basket weaving, for instance, and graduate with a 4.0... how much will this say about your ability to withstand med school? Now, if you major in physics with a concentration in quantum mechanics, with a GPA of 3.7, does this make you a better candidate. I'd argue yes (back to the workload argument). (note that once your GPA goes above, say, 3.7, you're in the golden spot, and it'll prob be more fruitful to work on extracurriculars than GPA).