I am thinking about a plasma - but have a question about resolution. The model I have been looking at - like many - has a stated resolution of 852 x 480. Does this mean that for best quality you need to play NTSC discs (480 lines), rather than PAL (576 lines)?? Is anything above 480 lines some sort of "interpolation"? I ask this as I don't have any plans to invest heavily in Region 1 DVDs, having built up a collection of Region 2.