I think the Toshiba HD-DVD XA2 is a stunning upconverting DVD player and can be had for a song if you can find one. It is what I use, and I don't own a single HD-DVD. Barring that, I'd go with the Oppo with its ABT-102 video processing. It also outputs 480i in case you want to use an external scaler.

561, DSP5500s, DSP5000C, analog sides and rears