I see someone said Stanford isn't what it once was.
When I was living on Stanford's campus from late 1989-early 1993, I thought it was the most amazing campus I had ever seen. I've been back once since, and it was still amazing.
So for me:
Stanford
Washington University in St. Louis -- beautiful AND impressive
Colorado College (amazing views from campus, so much like Pepperdine, it's the surrounding area that makes it so beautiful)
Vassar College
Kenyon College (for sure the best in Ohio)