Sure, if all you care about is music, than 5 M80's or M60's all around would be ideal. However, I have all different speakers around and DVD-Audio discs sound amazing. The trade off between the quality of music and the price would probably not be worth it, but if you have the money and do not care about HT at all, then go for the towers all around. It will sound awesome if you place the speakers right in your room with minimal accoustic problems.
You would also need a sub to go with it since 5.1 music also has a sub channel.
