I'd say Tascam. I have been scavaging vintage ones since last year. I believe Denon, Studer, Revox, and Marantz all have their studio lines of CD players. Their retail goes from a little over a thousand to several thousand. I believe that quite a few broadcasting companies/studios still use Tascam CD-601 today. The CD-401s are seen around more often in smaller personal studios, and CD-701 and CD-501 are hardly seen perhaps because of their age. These are the retired line of Tascam CD players that were built like tanks, and I prefer them over many other components I've heard. I have not had a chance to hear some Revox/Studer, but these are suppose to be great too. Sony has its line of professional CD players, and they seem to offer much more of an analytical sound.
On purchasing these things, there are hardly ways to get around the high pricetag in trying to get anything good. I would look used, but there is a good chance to run into units that has uncountable hours on the laser pickup, as that seems to be the part that screws up the most. I have dealt with two Tascams that had trouble with their laser pickup mechanism(Sony KSS151A, a magnetic suspension pickup?). It costs around 75 dollars to just obtain this part for replacement, but it is fun shooting for used pro equipments.