Lots of speakers in all price ranges sound good. What I hear when listening to the expensive stuff (here my experience is with the Wisdom Audio M-75)is that they do everything well. Lots of affordable speakers will get part of the frequency band right but fail miserably (usually in the deep bass) elsewhere. Also, I find line source speakers to generally be superior. Whether the price is justified or not the line source speakers I've heard (and the line source emulators like the Pipe Dreams) tend to be expensive. You get what you pay for.
Are more expensive speakers better?
Recently, I found out an interesting thing while reviewing audiogon threads. Many people were not satisfied with their current speakers and were trying to "upgrade" their system, seeking other people's opinions/advices/recommendations. And most people used the phrases like "best bang for the buck" or "at that price range". Does that mean more expentive speakers are better?