At both UIUC and Washington, many majors are selective admission (meaning that you need to do more than pass the prerequisites with C grades or a 2.0 GPA):
http://dgs.illinois.edu/declaring-your-major
https://www.washington.edu/uaa/advising/academic-planning/majors-and-minors/list-of-undergraduate-majors/
Consider your possible majors and see if they are selective admission, and how selective they are, at each school. Obviously, some majors like CS and engineering majors are highly selective at both schools.