Taking music that is familiar to you is good advice. Keep an open mind about what you are hearing rather than thinking about which speaker is playing, in other words, don't look...listen. You'll likely hear a difference between the towers and the M22 if a sub isn't used, but it'll be an interesting comparo otherwise. Also listen to them at a level you will play them at most of the time, but turn them up/down to see how you like them at higher/lower levels.
I read a while back, that Holly Cole is popular among some installers to set up/test audio equip't if you or Axiom happen to have her music available.
