:text-+1:Rope said:That all depends on your equipment's ability to up convert 480p to 720-1080p. It's much easier for equipment to down convert (eliminate lines of resolution 1080p to 480 - 720p) than it is to up convert (interpolate/add lines of resolution, 480p to 1080p).
Be selective in choosing the disc you replace. A quick search online will give you some idea whether or not it worth the price of admission.
Rope
Some movies known for their eye-candy can really benefit from higher resolution. Others, such as comedy, drama and musical, it may not be worth the extra cost if sold that way.