Is it worth spending $10k on CD-only player today?

Not that much for source equipment. However, first thing is to analyse what do you listen most, and for hi-rez - how many of the available titles you'd like to purchase right away. It's not about technology. It about ability to use it. I like idea of hi-rez, but would not invest 5-10K into it, unless I have truly unlimited choise of hi-rez music, which is not true at this moment. Taking into account that virtually any hi-rez player compromises redbook playback quality, which still prevails, my 2 cents - go with redbook. And ask your question again in 2-3 years. ;)

This above would be correct if you can just stop listening CDs at all, and concentrate on SACD and DVD-A. But it isn't likely the case. Most of us have CD collections and substantially less hi-rez music. How are you going to enjoy all those all good CDs without nearly-perfect-to-your-taste CD player? Take Linn Unidisk for example. Nice, well built universal player. Now, just as among CDPs, its sound may be not exactly as what you are looking for. Unlike CDPs, where on healthy $3K level there are plenty, plenty of wonderful CDPs, how many alternatives to that Linn you have among Universals? I mean - real alternatives, too many modern Universals around $5K don't play Redbook CDs as $2K CDPs do. There is no enough choice - not for players, nor music. Well, one could keep good CDP AND good hi-rez separately, which would solve anything mentioned above. But to trade good CDP to the same price range SACD/CD player - not now. I listen to music, not technology.

This above would be correct if you can just stop listening CDs at all, and concentrate on SACD and DVD-A. But it isn't likely the case. Most of us have CD collections and substantionally less hi-rez music. How are you going to enjoy all those all good CDs without nearly-perfect-to-your-taste CD player? Take Linn Unidisk for example. Nice, well built universal player. Now, just as among CDPs, its sound may be not exactly as what you are looking for. Unlike CDPs, where on healthy $3K level there are plenty, plenty of wonderful CDPs, how many alternatives to that Linn you have among Universals? I mean - real alternatives, too many modern Universals around $5K don't play redbook CDs as $2K CDPs do. There is no enough choice - not for players, nor music. Well, one could keep good CDP AND good hi-rez separately, which would solve anything mentioned above. But to trade good CDP to the same price range SACD/CD player - not now. I listen to music, not technology.