In my experience, colleges do indeed value arts classes on applications. They often look for well-rounded students who show a variety of interests, and arts classes demonstrate creativity and a willingness to explore different perspectives. Not only does this show a student's ability to balance academic rigor with creativity, it also indicates a broadened worldview. However, the significance of arts courses will vary from college to college, depending on their particular values and focus. It's always a good idea to research a college's perspective on this matter.