Dred,
The Oppo 971 would be the perfect DVD player for video connected to the DVI input on the Mitsu. I think the audio is pretty good too. If you are more concerned about the audio, the Oppo 970 is supposedly sounds a bit better, but is not quite as good for video.
Either way, you should be in good shape. The Oppos are hugely popular and you could re-sell one for only about $30-40 dollar loss if you don't love it. You may find that it is so good that you just keep it till it dies.
BTW, are you using it for movies only or is it also your primary music player?
Enjoy,
TIC