I've been watching it on my HDTV(16:9) and the image quality varies drastically.

The main problem is that while the show was filmed for widescreen, the CGI was only created for a normal(4:3) TV. The filmed portions of the show were recreated from the film, and except for scratches, it looks excellent. I have a progressive DVD player which recreates the 24fps film images. ([link|http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html|This] is an excellent description, with animated images, of how progressive players do this)

In contrast, the CGI portions look really-really bad(this includes any live action with CGI effects). This is a shame because the CGI looked sooo good when the series was aired. They took the 4:3 video source, cropped the top/bottom and then scaled the image to eliminate the black bars. The resulting image looks very soft and blurry, plus the scaling exaggerates the problems with interlaced video.

When watched on a 4:3 TV, the DVD player will toss out every 4th scan line and letterbox it for playback. The filmed portions should look fine. I'm curious about how the CGI portions look. If the dropped scan lines are exactly the same as what was added to to fill a 16:9 set, then it should look really good on a 4:3 screen. However, it's possible that the dropped scan lines are not the same and the end result would look as crappy, if not worse, than on a 16:9 screen.

My set doesn't accept a 720p signal, my HD decoder converts ABC's 720p signal to 1080i. The conversion makes ABC shows softer looking than the other channels which use 1080i.

while NTSC has 525 "lines" of resolution, quite a few of those are not shown. [link|http://www.udayton.edu/~cps/cps460/notes/displays/video_standards.html|Video Standards]

A standard American TV broadcast has 525 lines per frame, but only 480 lines or so are visible. About 10% or 45 lines are lost during vertical retrace.

HDTV standards chose to use what's actually shown when specifying the format.