Sony has just released a video that directly compares the original Final Fantasy X, which came out in 2001 for the PlayStation 2, and the upcoming high definition re-release, part of the Final Fantasy X/X-2 HD Remaster package, slated for both the PlayStation 3 and PlayStation Vita later this year.
And as you can see… there's a difference all right, but it's nothing all that crazy dramatic. Sure, textures look better defined and all, but that's about it. Also, some might take issue with the fact that the colors look brighter in the SD version, though the HD version does handle blacks better.
If anything, the above simply demonstrates how remarkable the visuals were for a first generation PS2 title in the very first place. Unfortunately, even know we still have zero clue when the release date is, other than "2013". Supposedly.