One thing to consider is whether or not the objective of your system is to reproduce as closely as possible the sound you hear in live music: the (dare I say it?) absolute sound. For better or worse, we all hear live music with the same ears and same hearing acuity as we do reproduced music at home. So I'd say, just do some auditioning and pick the speakers that come closest to the live experience. Of course, I understand that's not what absolutely everyone is after.
