64-bit Far Cry Image Quality
Performance is only one aspect of the new Far Cry patches - the biggest impact will be visual. The visual improvements in the new patches are definitely noticeable, but not across the board.

Hold mouse over image to see the same scene with the new 64-bit patches applied.
For example, the improvements range from very subtle in some levels (see above) to major in others. The improvements in the Pier level are quite bold as you can see by the screenshot comparison below:

Hold mouse over image to see the same scene with the new 64-bit patches applied.
The differences in the Pier level are numerous. First, the improvement to draw distance is very noticeable:

Hold mouse over image to see the same scene with the new 64-bit patches applied.
You can see additional detail in the rock textures:

Hold mouse over image to see the same scene with the new 64-bit patches applied.
And finally, the water looks a lot better in the 64-bit version:

Hold mouse over image to see the same scene with the new 64-bit patches applied.
And of course, there are the new levels that are only available to those running the 64-bit version:


Final Words
Although AMD and Ubisoft are definitely trying to provide 64-bit gamers with added value, it's honestly going to take games that depend on the benefits of a 64-bit OS to really sell the gaming population on 64-bit. For fans of Far Cry, there's no reason not to try the new patches, but we wouldn't expect a mass exodus to x64 Edition because of the content that's been enabled here.
AMD's goals are quite admirable, but the fact of the matter is that none of the visual improvements enabled by the Far Cry patches had anything to do with AMD64 or EM64T. They are artificially limited to run on those platforms alone, but could work just as well on a 32-bit platform.