Speaker Cables? why all the hype for expensive speaker wire?

Right on, Hilde, MC, Nonoise.
We are dealing with abstractions. Abstractions are abstract because they defy concrete explanations. We should welcome and commend the contributions made by the righteous electricians to our understanding of cables, switches, fuses and all the other "snake-oil" we enjoy at sometimes extraordinary prices.
Please, will one of them prove empirically that all cables are the same.

Good one.

In my experience:
1. There are systems where cables matter a lot, and some others where the difference is smaller (usually less resolving systems but there must be more to it than that). For example, a friend of mine has nice vintage Tannoy speakers, where not only cables but even source components seem to make little difference ;) 
2. I agree some cheaper cables can let you "hear more" but it doesn't mean the sound quality is better. It may be because the bass is weak, you perceive more in the mids or highs. Or sometimes there seems to be less bass but it's better quality and you learn to appreciate it more. 
3. It also always amazes me how different the cable breakin experience can be with different people. For example, when I get a new cable with Furutech rhodium plated plugs, it takes months in my system before it sounds beautiful, whereas some other people claim to have the same experience on the first day... 
4. Comparing cables can be tricky as even the well brokenin cable may need time to settle after it's disconnected and reconnected...

Re 3 and 4: I'm sure it's not a question of "adapting" - my Furutech cables sound from absolutely "horrific" to absolutely "magical" over the long months of breakin. It's from "no soundstage" to "deep and wide soundstage", it's from "harsh highs" to "magical highs", it can't be a question of adaptation...