If you cannot see the difference you must be blind
http://forum.blu-ray.com/showpost.ph...71&postcount=5
Look at some of the images in the links and tell me again you cannot really see the difference.
Sure if you watch a blu-ray and then the DVD version after you might not notice, but side by side and you can tell a mile off.
Even old films look significatly better in HD than SD.