Thanks for your question. We tackled it in this week's newsletter, but in case you missed it, here's the response:
Since they're designed to deliver the full range of sound to all speakers, DVD-A and SACD sound great in two-channel mode as well. Your receivers and speakers are up to snuff, so you will probably hear a difference with DVD-Audio and SACD compared to CD. We'd recommend a universal player like the Pioneer DVD-563A, which can play both formats.
At present I'm using an Onkyo TXDS787 a/v receiver with two excellent floor-standing speakers - and it may be a while before I can get the speakers I want for a complete surround sound system. I'm very interested in DVD-A and SACD sound formats, but am wondering - would it make any sense to invest in either of these without having a full surround-sound speaker system? Are there any benefits for a two-speaker system?