The problem is that there are no real set rules to go by to produce consistent high quality videos that will still be "viewed" as high quality down the road. With every change of technology, the rules change. I believe we are not alone on this. Television broadcasters face this same challenge. Not everyone has HDTV or 100% digital capability yet...the smoke will take along time to actually settle.
As a kid, I recall my dad's old super 8 projector. We would pull up the screen and fire off a movie then have to adjust the focus of the lens to find the sweetspot to watch the movie. It's not like a projection room or a theatre of course where the projector is in a fixed location. The only thing constant was the film itself and the size and quality of the projection screen we used. WYSIWYG!
I go into a lot of homes in my business. The vast majority of people have CRT's in the 32" or less range. As these units are being replaced, they look towards the "newer" and "larger" technology. Based on this I would say currently the
"biggest audience" is the CRT group.
If I were designing a webpage, I know it may not look good on every computer that views it for a couple of reasons. One being the web browser that a user uses to view it and the resolution and quality of the monitor they are using. To combat these variables, a good web designer, tests the webpage using the various available web browsers at several resolutions. Before LCD monitors, you only had CRT's to deal with. The difference being the DPI and resolution capability of the various monitors. LCD's may never achieve the true picture quality of a high-end CRT though...but they are getting very close.
From a practical standpoint, it became quite obvious that setting your own display resolution to 800x600 when designing a webpage is the smartest thing to do. There was a point where absolutly no one had CGA or EGA monitors anymore and everyone had at least a standard VGA monitor that could display at 800x600. This is still a recommended practice I believe even though not all web designers follow this.
Creating a video that will look good on everything from a 4" CRT to 108" LCD or plasma is the challenge. Economically, I cannot afford to buy every imaginable tv set out there to test my video on. I believe there is a work-around for this though.
After shooting and editing a video on the computer, save it back to tape. Besides archiving, this preserves the DVI-AVI in its native format. Then take the camcorder to the local electronics store and pretend to be interested in buying the most expensive highest quality thing on the market. Of course you have to talk the salesmen into letting you plug the camera into several models maybe.
Professional DVD production houses generally request you send them the movie on a DV tape of some type. Some accept movies on a hard drive. But what they really want is the movie in it's "uncompressed" format. That way they only have to deal with the 4:3 or 16:9 ratio, the FPS and the length of your movie in time. They also don't have to deal with the limitations of 4.3 gb blank DVD. This is why you can have a two hour movie with lots of extras on a commercially produced DVD with no noticible quality loss from the origional. This also explains why commercially produced DVD's look better on a wider range of TV sets than homebrew DVD's.
I imagine that in producing commercial quality DVD's they achieve this in part because they work from the origional. Also they likely are able to encode the video using less compression and at higher bitrates.
I think the real bottom line here is the intended audience. If you are producing movies or videos for yourself your job is much easier. It only has to look good to you on the equipment you have now. A portable DVD player hooked up to a high-end tv at the electronics store would also let you see your creation as others may see it should you choose to increase your audience base.
I think the rule here though is that the higher the overall bitrate you are able to achieve when creating your DVD, the better the quality the images will be on the larger screens. The larger screens being capable of processing and displaying more information filling in the spaces so to speak to compensate for the video being stretched to fit. The smaller screens would actually be visually compressing the image and appear to have a higher quality.
The best we can ultimately do though is work within the limits of our imagination, our audience, the time and money we have to invest.