A document camera is always a great start. I love introducing music to students by putting it up on the document camera. This way we can analyze the music as a class. We can even make changes to the music as a class.
Interactive white boards are nice because there are so many music games and lessons made specifically for SmartBoards.
Last I would say having the ability to record students is a nice addition to a music classroom at any level. This forces them to focus more, take pride in their work, and get hands on experience using digital recorders.