A few upscaled DVD's i would say look close to HD are:
1.The Warriors - The Ultimate Director's Cut -
I cannot believe how good color saturation,detail,black levels,lack of artifacts are in this version and the movie is now 28 years old for crying out loud,i will be picking this up again when it is released shorlty on HD DVD from paramout.
2.Reservoir Dogs: 15th Anniversary Edition -
Another unbelievable transfer upcoverted,very sharp picture with vivd colors,this version detroys the older version in everyway.
3.Star Wars Ep. 1
The job they did restoring this and while being upcoverted looks do not disappoint and picture has pop for movie 30 years old now,This is a MUST have HD DVD when it comes out
Funny thing is there are alot of titles that are newer and i mean alot newer than these but these stand out to me because of the wow factor i found when watched upcoverted for a standard DVD imprssive stuff even though the are not True HD-DVD still impressive,most impressive.