Also, upconverting players themselves vary wildly in quality. The cheaper ones look horrendously awful (generally). It almost seems like they DOWNconvert. Then there's others that upconvert beautifully. I don't know much about the Oppo's, but I can tell you that the Denon 1930CI I have is insanely sharp and crisp. That's my recommendation.
If you don't have HDMI on your TV, you can get an HDMI-to-DVI cable to connect the DVD to your TV that way, and I believe they have quality equal to a straight-up HDMI connection as DVI is also digital.
Edit: Just studied the Oppo that FIat1 posted up there, and it has the same upscaling process as my Denon (Faroudja technology) plus it has a DVI output it seems... that might be your ticket as well.