HDTV Forum

Mike, Brian touched on many points and touched is the operative word here regardless of the length of the reply; this site is chock full of deeper explanations if you are interested. Some good starting places...

The FAQs in this section
viewforum.php?f=37

Video Waveform
viewforum.php?f=103

Calibration
viewtopic.php?t=4450

Putting a few things in perspective...

No - a 26" display is NOT considered a legitimate HD item ...

To clear the air, size is not what makes a display HD. It is the pixel matrix, preferably 1280x720 or 1920x1080 with 1920x1080 readily available and 1280x720 nearly impossible to find. Simplistic category labels of 720p and 1080p do not provide this information because all that means is there are at least 720 or 1080 vertical lines (there can be more which still qualifies) while telling you nothing about the other direction; check the FAQs. Your ability to fully resolve detail is directly related to your viewing distance, about 3-4 screen heights, and it is the viewing distance from your comfy chair to your current display that determines the correct screen size for your fully resolved HD experience!

but - you needed to have gotten a much larger than 26" display .... that is an extremely-limited viewing "choice" - - should be viewed from ~ ~ 25" - 30" tops

Eli meant the same thing and was merely pointing out that in the real world few people watch TV for hours at such short viewing distances and that is why smaller displays are rarely recommended or considered a realistic option for a true HD experience. Get far enough away from any HD display and it is no longer HD, just real clean; get far enough away from an old TV so you can

Just my 2 cents....
You imply the DVD players (plural) you are using have HDMI as well as Component outputs.
Regardless of the type of DVD player (progressive or upconverting) the Component outputs will provide only the DVD resolution (480P). The component connections are analog so the DVD digital source is converted to 480 analog by the DVD player. The TV must convert the component input 480 analog signal to digital and then to the native screen (720/1080).
With an upconverting DVD player via the HDMI interface the DVD player can output the DVD 480P upconverted to 720p or 1080p as well as 480p. By setting the DVD player configuration to output 720p or 1080P you have the DVD players software convert the 480P off the DVD to the specified resolution.
In any case, your TV software will have to take the input (480 i/p over component or HDMI, 720p or 1080p over HDMI) and display it on its fixed pixel screen. If the TV fixed pixel screen is not the same as the input it must convert it to the native screen resolution to display it.
So when you connect via component cables you are giving the TV the 480i (480p if progressive scan) and the TV sets software converts it to the native screen resolution. I would expect this sort of conversion by the TV to be pretty good since 480 would kindof be the default input from external STBs (cable, satellite, DVD).
With an upconverting DVD I would try setting the HDMI output to upconvert to whatever the TV native resolution is (so the TV doesn't have to change it) and compare that result with the results with the DVD HDMI output set to 480p. This would be checking for differences between the DVD doing the 480 to native conversion verses the TV doing the 480 to native conversion. Then settle on the better result and do the TV alignments (preferable using a setup DVD) mentioned in previous posts.
I would not expect the component interface to provide the better result due to maximum of 480p and the extra analog to digital and digital to analog conversions necessary.

good luck..