It looks like you already have a concensus, but I just wanted to add something. I've got a 5.1 system that I love and use quite a bit for music playback. I always felt the default setting for the center channel was too loud and actually robbed some of the imaging I was able to achieve with my front 2 speakers. When I say imaging, that includes depth in particular. Others here have said the opposite, but that's been my experience.
I agree about getting a better sub, though I have to admit that I'm not familiar with the Klipsh you have. All I know is that I LOVE my SVS sub and wouldn't give it up.