The biggest appeal of the very selective schools is that just about the entire peer group will be smart and interesting.
At a safety school, there will be a variety of levels of past achievement. The trick, I think, is to find a school where one will be able to find a micro-peer group of motivated students. Honors colleges are one attempt to create a more elite environment in a big school. But, just like high school, particular courses and areas of study will attract better students.
And there's one advantage of not going to a school where every other student is at least as smart as you are: the possibility of earning a high GPA and accumulating honors is greater, a plus for admission to law school or med school.
That 30,000 student school may have lower average stats due to in-state admissions policies, but the top end of the bell curve will contain some amazing people.