I have a Sony ES series megachanger that I bought used from the HD forum a couple of years ago. I was going to buy an upsampler and DAC too, but I was very happy with the quality of the sound in my casual listening system.
The thing which really made it work was hooking it up to an old laptop with a Slink-e (see
www.Nirvis.com). My laptop is hooked up with a wireless card to the internet and with the Nirvis Jukebox software automatically built a database of every CD, artist, and track. I am not associated with Nirvis in any way, but I highly recommend the Sony, Slink-e, laptop, internet arrangement. You can build playlists with your favorite songs from different CDs, print off lists of CDs and artists, search for an artist (it even finds them on compilation CDs like Woodstock or Montery Pop), and so on. And you no longer need to find the CD, get it out of the case, load it, etc.
Here is a screen shot from the Nirvis webpage:
