These are basically on the endangered species list anymore. I assume that you are referring to a CD only changer. I've been around the block a few times on these units. I've tried a Denon DCM-370, Yamaha CDC-685, Adcom GCD-700, and a Sony 70ES. Out of all of them I liked the Yamaha and Adcom the best, followed closely by the Sony. Didn't really like the sound of the Denon. I thought it was leaving itself short on the frequency range. The Adcom really liked the bass, and the Yamaha and Sony just flat out sounded clean.
Not knowing your price range, I would recommend the Yamaha, Sony, or Adcom in the $200 or so range. I got my Adcom used off of ebay for about 2 bills. Got the Sony for $45 as well, and probably should've kept it, but oh well. Right now, I have a Yamaha CX-1 DVD changer serving as a CD changer when needed. It's got a pretty good audio section in it. If price isn't an issue, then check out the Rotel 1055. Never heard it myself, but always read good stuff about it. There are several other manufactures out there that you can find changers from on ebay in the $200 - $400 price range, including NAD, Parasound, Nakamichi, and a few others. My latest thought is to mabye pick up an old school Carver changers. My brother has one hooked up to some 10 yr. old NHT 2.3s, and for a 2 channel system that baby smokes!
For redbook CDs, the Rotel RCC-1055. Pricey at $600-$700 new, but probably the best 5-disc changer out there. The discontinued Sony ES SACD/CD changers are also excellent (222ES, 333ES and 555ES). You can find them used from around $250 to $500.
I was in the market for the same thing you are about a year+ ago. Looked/heard a lot of CD changers but went with the Parasound CD/C 1500. Amazing sound out of a changer. Bought mine for under $200 and it was a steal. Built like a tank and the sound is as good as many single CD players I've had. In second place was the Sony ES line. Good luck, and just shop around on audiogon as these show up there from time to time.