I'm a bit curious about the sound formats of DVD-A and SACD. For those who have actually listened to music in those formats is there really a signficant difference in sound quality? Outside of the media players would a person need high quality speakers or a high end reciever to take advantage of the improved sound quality? Can either DVD-A or SACD be reproduced on a PC? (I've heard someone say that most PCs are'nt able to accurately reproduce the sound quality)