sparkey - in other words audiophiles would be able to tell the difference.
Audiophile is a charged term, often associated with stuff that many people can't hear, or that just seems completely goofy. I know a lot of people who would easily hear the difference but would not accept that label. There's a big difference between "good playback", spending where it counds vs. "audiophile"...
Based on the posts, there are lots of folks on this board who have bought and sold a lot of playback gear over the years.. You might be amazed at what can be heard, and how much better some gear sounds than other gear. Some people assume amplifiers sound pretty much the same. I mean, they're just solid state amps, right? I can recall the eye opening experiences where I found that isn't true at all (oh how my wallet wishes it was), and how it caused me to ignore specs. Then there was the first time I heard a soundstage that imaged way outside the speakers, something I didn't think was possible... The good news? The cost of great playback has come down, and we have sites like audiogon.
As Todd said, it is often easy to hear the difference in gear, but it takes a lot more time, and can be difficult to decide, which you prefer. Especially when you're comparing great sounding sources. I find it takes different types of material, different types of recordings, considerations of listening fatigue, etc.