It is not true and it is very far from reality to say that you can not get good sound out of moderately priced speakers. I have heard multi-thousand dollar setups with very expensive speakers, and they sounded very good but know what, the difference with moderately priced ones, or DIY ones, in a good placement it is not comparable to the difference in price. I dare to say that most important in speakers, being decent, is the right placement over the price. Place them poorly and you will have a miserable setup, it doesn't matter how much you pay for it, thousands or millions...any good studio monitor will give you faithfully presentation and very good sound, ones better than others, and mainly all of them cost under $1000.00...JBL and Polk that were used above as synonym of cheap brands have good speakers both, old and new, you just have to choose, not all what you can find is good...Axioms made very good speakers as many others in that price range, for classical, for jazz, and for whatever you want to listen to...BTW Steve classical music is not superior to any other genre in recording quality, nor in performance, and you can find good recording in any kind of music, and I have heard more crappy recordings in classical than in jazz for example...Telarc offers very good quality recordings, and a lot of jazz musicians record there nowadays
You can get some of the best drivers ever made for under a grand, make a good box out a very good materials and you will have a very good speaker for real cheap...Skan Speak, Vifa, Morel, HiVi, Seas, Peerless, and many others made extremely good drivers for speakers for cheap...there are very good DIY kits for those drivers around, you just have to choose wisely, now, be careful if you do not have the real state for an speaker setup, do not waste your time, you will never achieve a good sound, and you will be better served with a headphone setup....
Now speakers versus headphones, price wise, another myth, the only advantage of the headphones is that the real state and the convenience of the isolation, my headphone setup is far more expensive than many speakers setups out there, and I'm not convinced of that nirvana yet...
The only reason I do not invest more in my speaker setup is precisely that, I do not have the space for a dedicated room for them, any cash on that will be miserably wasted...