Thanks everyone for your thoughtful and encouraging responses.
Just to reassure everyone, I really never had any intention of running out and selling all my stuff in a maddened state of disbelief. And if pushed, I guess I would concede that it's not overwhelmingly surprising (maybe just a little surprising) that I would prefer a much cheaper system to a really expensive one. But what really did surprise me is that the differences between what I heard in the store and what I hear in my house were so extreme that my leaning towards my own gear ceased to seem like "personal preference" and began to seem like "objective superiority."
I really anticipated some sort of revelation while listening to really expensive gear. Not the sort of revelation that says, "This is what a really great system sounds like." But maybe, "This is what it sounds like when X, Y and Z are done really, really well. Maybe you'll like it and maybe it won't be your cup of tea, but at least you'll truly appreciate what it means to do X, Y and Z really, really excellently." And I just didn't come away with that feeling.
The sound had almost no life. It was like trying to watch a really huge, really bright television with extremely vivid colour reproduction, but someone had dropped a semi-transparent shower curtain in front of it. Strangely, the shower curtain had a bunch of holes in it, so portions of the image just jumped out and screamed at me. Taken individually they were brilliant. But who wants to take them individually? The rest of the music, the stuff that makes the whole hang together, just seemed bland. I wondered whether someone had shoved cotton wool into my ears. Not only was this not what I wanted, it was not the sort of failing that I anticipated.
Anyway, I certainly don't imagine that all experiences with super expensive gear are likely to be this uninspiring. And it wouldn't surprise me if future experiences with very similar systems turned out far better - maybe the room, or the proliferation of speakers interacting around the place, or a bad sounding disc or something else just distorted my experience.
But having spent a lot of time yesterday enjoying how my system sounds, I decided on a way to characterise my most important priorities in sound: I will always prefer the syetem that is more likely to make me play air guitar.
Chad