<p>Go past the name brand. Visit the school. Tour the E-school. Find out about research opportunities for undergrads in all areas (yes, you may switch your focus). Despite rank, you may find that one school is researching something that really interests you, and overall just feels like a better fit. This will most likely lead to an overall better undergrad experience which will give you a better resume when applying to grad school. If you are not happy, it doesn’t matter what school you are at. You will not be as involved and it will show.</p>
<p>To answer a more basic form of your question, no, not all state flagships are created equal. However, there are students that choose solid state schools, attend their honors colleges, study abroad, have excellent internships, and are very, very successful in getting into top grad schools. As a bonus, they usually have money left to pay for grad school because their undergrad was heavily funded by merit aid.</p>