You're question is a bit confusing...but I will try to answer:
"Do HDTV and/or HD DVD Players improve Burned DVDs?"- not sure what you mean about that, but the way I understand it- the HD TV alone is not going to improve the quality of your DVDs, unless you have an upscaling (HD) DVD player to go with the HD display, that will indeed improve the video quality of your burned discs. The player doesn't have to be an HD player, it can be a "regular" upscaling DVD player.
HD DVD players also work on burned Dvd's like DVD-R with burned divx files??- I am not aware of any HD DVD player that is Divx certified. There are some Blu Ray(or will be in the close future, don't know if are yet released on the market , and too lazy to Google it), that wil play Divx video files. However, even if already on the market, the price would be a bit too spicy!
