Before I give you the link to some sample images of before and after processing let me say a few things.
You try to get the image you want by manipulating all the variables on the camera, choosing the right lens, framing the picture, etc. But you often just don't have the light you want or the time to set up the shot as you'd prefer. So you click the shutter release and hope you can fix it back home with your post-processing software.
Sometimes the problem is bad lighting (too hot and contrasty in the middle of the day or not enough light indoors, etc.). The human eye and brain, of course, are able to make sense of some very challenging lighting situations. The human eye is much more sensitive to relative luminance differences than the best and biggest digital sensors. What this means is that most, if not all, digital captures with even the best cameras will need some post processing to compensate for the difference.
Sometimes you know you could make the light work if you have thousands of dollars of lighting equipment (like Joe MacNally) and a couple of hours or more to set things up. Sometimes a little fill light from your speedlight or reflected light from the sun will do the trick. But often you don't have the time to set up for a complicated shot. So you shoot a couple of shots at different settings as quick as you can and hope one of them works. I could never do that with film cameras because every shot cost money. With erasable digital imaging you can click the shutter liberally and not worry.
Not every image requires as much post-processing work. If exposed and composed correctly, most don't need much more than a few adjustments to the lighting and some sharpening. The images I've posted require a lot more than that.
Okay. So I've downloaded some "unprocessed images" for you to compare with the finished product. It's not entirely true that these are unprocessed images. The camera, of course, always does some processing. And the "unprocessed" images I've posted have been converted from raw NEF files to JPGs. I can't post a 26 MB raw file on my Smugmug sight. The 14 bit raw files have a huge amount of detail - much more than you can see. All that detail is accessible in Photoshop or Nikon's Capture NX. What you see here is what the unprocessed images look like before I start tweaking it.
I've put the unprocessed image first, followed by the final processed picture. You can switch back and forth between them using your left and right arrow keys.
UPDATE: Hey, I've added another example and some comments to each photo. The added example shows what a little "cloning" (removing objects) in Photoshop can do for an image.