I'd say that the 557 would be worth it, but you could always try a 556 first -- should you decide to upgrade later then you would probably be able to sell on the 556 for about the same as you pay for it, but if it works well enough for you then you might be happy to stay with it. I see that Steve beat me to posting about the 568... I was a bit slow typing and didn't see his post until after I'd submitted. Given your interest in migrating to a streamed front end then I'd prioritise trying to find a 568 for a good price, while keeping an eye open for a Meridian amp. Your 200 series CD player would get a boost from the 568 as a DAC too.