My school is unranked in my field and certainly not a flagship. I chose it because it was close to home and lowered my costs. My GPA wasn't even close to perfect, but good research experience and publications, along with a strong resume and SOP (asked a lot of people for help) got me through my applications. Grad schools judge by a lot of things, and coming from a big name undergrad is, from my experience, not very high on that list.