I'm slowly going back to many of my best photos and seeing how I can improve them with the magic of Photoshop. One it's a good lesson on learning this incredible program, and two, it usually makes them better.
Here's another before and after from my current learning how to use Photoshop. Now this isn't a pure test of Photoshop's impact on a photo because I did redo this from scratch. But there were a number of areas where Photoshop gave me the ability to improve this photo. The reality is that it is subtle differences but look at the left side of the church below the top round window in the before photo and you'll see a blue color cast. I was able to remove that and bring a more consistent look throughout. There were a number of other issues as well, but I won't keep you any longer.
AFTER (New Version)
BEFORE (Old Version)