Practice rooms. As many practice rooms as possible. A MASSIVE library full of scores, biographies, recordings, analyses, music history, and pretty much any other type of book you can think of, from as many different views as possible. Some sort of system to get musicians in the school in touch with each others. For example, if a composition student wants to find string players to play a string quartet, instead of having to hunt down string players around the school by awkwardly asking random people if they know a string player, the composer can instead have access to some sort of database that lists all of the students, their instruments, etc. This would be beneficial for the instrumentalists as well as they could use it to find other students to start small ensembles with, or to find composers to write for their instrument. Lots of concerts is obviously important. A good balance of genres and styles. Don't emphasize any specific era (especially contemporary, as many schools seem to). Over emphasizing an area tends to alienate students who are not interested in a particular area, or on the other hand are already well versed in that area, but not others. Never assume your students already know a piece or composer. There are plenty of students who may just be coming to your school who come from a small town and have never heard a string quartet live before, or an orchestra. That leads me to my next point. Understanding for those who come from "outside" traditions. A lot of students don't grow up in households that listen to classical music, or that encouraged classical lessons. Many students pick up the classical tradition only a few months before going to college because it is required for auditions. My experience has been that there is a large assumption that every music student has already heard, studied, and played every piece by Bach, Mozart, Haydn, Beethoven, Tchaikovsky, etc. live. The professors and faculty need to be understanding of students who are not familiar with these pieces, and not be frustrated when students find these pieces more interesting than the pieces the professor may find interesting.
That's all I could think of off of the top of my head.