Should I set the DV600 to 720p or 1080p when watching dvds? My plasma is 42PV8
If you set your Pio DV600 to 720p or 1080p, the player is doing the upconversion of your dvd movie. But the 720p setting is better choice because you will only do one upconversion process done by DV600. On the 1080p setting, your DV600 will upconvert to 1080p then will be downconverted by your PV8 because PV8 cannot directly read 1080p since it has 720p native res panel only. The norms is, better if less conversion being made so less adulteration of the original signal.
But based on my experince (mine is DV600 and PV70) the best setting is DV600 outputting 450p via HDMI to my PV70. In this setup, my DV600 is not upscaling the DVD signal, it only deinterlaces it and directly output the 450p DVD native res to my PV70. My PV70 is doing the upconversion to 720p using its intrnal Vreal2 upconverter engine (720p is the native res of PV70 panel, like your PV8). This for me is the preferred setting because the PV70's Vreal engine upscaler is much better than the DV600's generic Mediatech upconverter.
Try the above settings and observe closely the fonts of your DV600's menu; you will notice big difference in font's clarity. Also, set the the DV600's settings to all 0's and Normal and do the image adjustments in your PV8 only.