I am not sure how to articulate this question, but I will try...

I have the 2005 50 inch Sony SXRD. I understand that this tv does not do true 1080p (1080p at 60 fames per second) and it takes a signal and de-interlaces it to 1080i and then it upscales it to 1080p/30 (1080p at 30 frames per second)

My question is what if the source (my Denon DVD-2930ci DVD player) puts out true 1080p/60 fps? Does the tv still takes that signal and de-interlaces it to 1080i and then it upscales it to 1080p/30 or will I get true 1080p through my SXRD? Not sure if I asked the question correctly, but will my television be any sharper with a true 1080p source or will I see no difference at all?

Second question is what are the VISUAL differences between 720p and 1080i? Which is better? What are the visual differences between 1080i and 1080p?