I am very happy with my muzieklokaal in Hilversum (Alberdingk Thijm College). It is newly rebuilt, and we have also just made a big investment in new instruments and speakers.
One thing which is good about this muzieklokaal is that it is on the ground floor, right near the front entrance of the school. Although it is not isolated and gets very noisy, it gives the impression that music is important to the school. After all, it is perhaps the first thing you see and hear when you come in .
The room, as you see, is divided between the "les-ruimte" and the "speel-ruimte." The ceiling, though not extremely high, is high enough which makes for more mental space. ICT plays an important role in the school, which profiles itself as "the laptop school" becasue every student and teacher has their own laptop computer. Thus I am often in the lokaal with thirty students who are all working on their laptops (for example, on the INTRO-website), with my computer connected to the beamer and projected on the large screen.. Next door to the muzieklokaal is the ICT-room, so I can have someone come in to help at a moment's notice.