Here is my opinion. There is no need to "match" a Denon DVD player to a Denon receiver other than perhaps for a common and/or duplicate remote. I would get the following features in a new DVD player:

1. Progressive scan
2. Five tray (you can sell your CD player)
3. Multimedia capability (MP3, CD-R, CD-RW, DVD-R, DVD-RW, etc.)
4. Pick one of DVD-A or SACD (You're going to want it in the future and it doesn't cost much more)
5. Good remote
6. Check what type of digital output you would need if you are getting low on digital inputs on your receiver
7. Karaoke feature perhaps??

You can get the above features for much less than $500.