This could get pretty subjective. I would say up to about US$3K, *most of the time* you get what you paid for, do those upper range speakers really cost that much to make? absolutely not. But there's always exception, such as companies like Axiom and Paradigms, they makes affortable great speakers, and in this case I do believe you do get MORE than what you paid, IMO the Axiom set a hardcore standard that NOT many companies can quite match, and this mean only one thing....competition. Eventually the rest of the competitors will be forced to either 1)improve their design, 2)put a lower price tag on their mid to higher level stuff in order to compete, or 3)create more snake-oils for all those suckers out there in order to maintain or generate more revenue. Don't forget technology is getting more advanced everyday, and WE, the consumer, definitely will be able to get much better quality products, more options, at an affortable price.
Also keep in mind that different stroke for different folks, My brother use nothing but KEF's reference stuff, do they sound good to me? yes, but are they good enough for me to envy then run out and grab me a couple pairs? nope. Because they do not sound as natural to my ears, they're way too laid back, not my cup of tea.
