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

I say no. No matter what the voodoo inside the player, the bottom line is that redbook CD just can't reflect all the advances in recording technology in the last 20 years. Surely anything worth listening to will eventually be released on SACD. I was playing with the idea of a mid- to upper-end CD only player to suppliment my SACD player, but I'm going to give it a rest for awhile. I'll bet expensive CD-only players with today's esoteric innards will come way down in price in the next few years.

I asked the same question, and my answer was "yes". My rationale is that there is an enormous amount much redbook product out there, and the fact all the new releases support that format means obsolesence just isn't an issue. I remain unconvinced about SACD's long-term success as a format.

Anyone who feels redbook is comparatively unlistenable hasn't heard some of the really good players/DACs out there.

This really begs the question "how many redbook CD's do you have?" If your collection is large (i.e. in excess of $20-30k) and growing, then a good redbook player may be in order. (I do think $10k is excessive however...)
If not, wait and see -- if nothing else, mod your existing player.

Spending 10k on a redbook cd player only would be very very hard for me. Unless it just sounds killer and can beat something like a Esoteric UX-1 which does all.

I just bought a Esoteric DV 50 ($5500 new) SACD-DVD-DVD-a and I have to say I'm pretty amazed. I'm not sure there is a significantly better redbook only player at this same price.

So, I got it all in one.

PS, my vinyl I still like better, but I now have access to some great music. SACD/redbook is pretty darn good though...

I'm not sure that it ever was.

In digital media sonic quality is ultimately limited by the finite amount of information on the disc. Playback equipment, no matter how good (or expensive) can only approach a limit imposed by the media. The information on a CD, 16 bits and 44.1 KHz sampling, is barely acceptable for audiophile recordings. The much greater information available on a DVD or SACD permits any decent DVD/SACD player to compete with the best CD players.