Throwing in my two cents-worth . . . many good observations in this discussion already . . . I started a thread which is still pretty current about integrating my HTPC and a standalone HT system.
After doing my casual window-shopping, I see that audio components are initially showcased at an MSRP and then marked down considerably. For instance, I picked a JBL Cinema 500 system that is still priced at the Egg for ~$800. Of course, I don't want to spend $800 for speakers, but I don't want to short myself in having to live with these components for a long, long time.
Turns out . . . . several resellers from J&R to Amazon/World-Wide-Stereo and others were offering this at a mark-down to between $323 and $350.
It just seems to me that showroom sales of audio components can vary widely, and resellers attempt to reap profits until the items become "last year's."
You can try and glean a sense of things from the reviews, but again -- much can be in the ear of the beholder. There's room for a lot of .. . . subjectivity. It's not like basic system components for a computer, in which you can get an idea of things like "over-clockability" and extra features. In those cases, there's not a lot of wiggle-room for price variability.
Sound systems -- receivers, speakers, other components -- that's different . . .