I was playing around with my Panasonic progressive scan player the other day. Flipping between progressive on and off there was very little difference. In fact, I'm not sure there was any other than mental :) It is a little hard to get a good A/B in that it takes about 2 seconds to switch and there is a lot digital noise while its switching... "better/worse... better/worse... A or B..."

I have the player routed through my Denon 3300 via component video (though the 3300 has a weakish 30mhz video switcher) and high grade component cable to a Pany PT500u 720p projector. (I do plan to get a receiver with 60mhz+ switching and a HD upscale).

So the question: is a standard (Blockbuster rented) DVD run through a progressive scan player really 480p, just 480i tricked to looking close to 480p, or the real deal?
I can't image a 480i DVD run through a 1080 upconversion really looks like 1080... but yet to see that either.

Explained in paragraph #3:

http://www.dvddemystified.com/dvdfaq.html#3.8

Your projector is a fixed pixel 720p TV. As such, it already contains internal circuitary to convert 480i into 480p and upscale to 720p. When you flip switch on your DVD player from 480i to 480p, what you really see the difference are the quality of progressive conversion of your player to your TV's de-interlacer. Same is true for upconversion. So, in the end, any PQ difference between an progressive DVD player or upscaling DVD player and a 480i DVD player is actually comparing the difference between external video processing and internal video processing of your TV. In the ideal world, you should see no difference what so ever feed your TV 480i or 1080p. However, in real world video processing hardware varies in many aspects. Some may do a better job than your TV, some may do a worse job.

wow that was a lot to read! So if I understand it correctly, a studio DVD does in fact output at 480p through a progressive player. However a home movie burned to DVD will be only 480i but perhaps enhanced a bit through upscaling.

So what about a 480p DVD run through upconversion, such as a receiver or projector with a good upscaler? Will the 480p look nearly as good as broadcast 720p/1080i?

So what about a 480p DVD run through upconversion, such as a receiver or projector with a good upscaler? Will the 480p look nearly as good as broadcast 720p/1080i?

You can't make up details that's not there in the first place. It will never be as good as true 720p and 1080i HD broadcasting.