Would you consider Mizzou a flagship state school? If so, I transferred from there to an "elite" school, and the difference for me was pretty huge.

Then again, I was a math major, and I've traditionally believed that math is one of the subjects where the school can make the biggest difference. There's a cultural aspect to math where being surrounded by a ton of extremely passionate and talented mathematicians is just impossibly valuable. At Mizzou, even the math majors didn't seem to care. I stood out like a sore thumb just for being truly passionate about the subject.

It can vary quite a bit depending on the area of study no matter which school you choose. Different flagship universities (and elite universities) have different strengths and weaknesses based on history and the faculty they bring in for research. An aerospace engineering degree from Kansas Univ. (for example) is worth more than a Mechanical Engineering degree from the same Uni. With Univ. Missouri-Rolla (for example) that might be completely reversed.