How will they look??

I was just wondering how well the DVDs that I've been burning onto single layer DVD-Rs with Shrink would work on:

1) A standard DVD player attatched to a 720P and 1080P HDTV
2) An HD DVD player attatched to an HD TV, since I know that the HD DVD players are supposed to upgrade standard DVDs to near HD quality.

I'm just asking because I'm thinking of getting an HDTV and I am curious how my collection of burnt DVDs will look on them since you have to have shrink compress them to fit on single layer DVDs.
Thanks all!