if you strive to be a great student, you'll probably experience your teacher as a great teacher. west chester university has lots of really experienced and knowledgeable teachers in theory, piano, orchestration, music history, pedagogy, vocal, instrumental and many more very specific musical topics (one specialist in vaughn williams). there are many summer trips that one can sign up for (one going to austria this summer) and many competitions (one for sight reading this semester).
i would say, don't just look for a good teacher, but a good school! there are so many different facets to music. it pays to take a lot of different topics (even in community college). i started out taking music history there, and it was cheaper. sometimes you will find a community college that is heading toward accreditation as a four year university (such as Antelope Valley College in Lancaster, California). it may already be, but the courses were VERY reasonable. it's more expensive on the east coast at universities - but if you can't afford the classes GO AND CHECK OUT THE BOOKSTORE!!! You can find lots of great textbooks to read and work from. Basically, that's what you are told to do -read the textbooks and research the topics in more depth in class.
Great teachers make you more and more curious.