I'm glad that here are lot of discussions about DVD recorders, but I'm missing discussion with this ultimate question (in the title).
My humble ideas regarding ultimate DVD recorder:
Necessary:
- DVD Recording 
- DivX player
- Burning format usable on PC (for recompilation and editing purposes)
- Reasonable price (up to 350$?)
- ...
"Would be good to have":
- HDD
- 5.1 analog output
- USB connector
- LAN (10/100Mbit)
- ...
What about: http://www.sigmatek-players.com/pvr-800/index.php?page=tech (305EUR)