Sedona - excellent question. You have uncovered a "dirty little secret" of some makes/models of progressive scan DVD players - many of them lack aspect-ratio control. This can be a problem because most HDTV's will lock onto their "full" mode when fed a progressive video signal. When this happens, non-anamorphic DVD's will not be shown in their proper aspect ratio.
The good news is that there is an easy workaround. Simply run the player in interlaced mode and you will be able to control the aspect ratio in your tv. Any progressive-scan player will allow interlaced output to make them backward compatable with NTSC tv's. If your tv has a killer built-in de-interlacer/scaler and it's not a huge screen, 480i from the DVD player will probably look very good to excellent. (I'm running 480i to my 16x9 Sony 34" XBR800 CRT monitor and I do not want for 480p from the player, trust me). On the other hand, if you need to rely on the player for quality de-interlacing, then make sure the player you buy will perform aspect ratio control. You could also use an outboard video processor box (Farouja, InFocus, etc.) to perform de-interlacing and they will control aspect ratio, too. Good luck! JZ