Photographers often get asked whether they use Photoshop on their images. There are many blogs out there that have talked about this, but I am going to add my 2 cents. It is often pointed out that Ansel Adams had his own version of photoshop, the darkroom. He manipulated his images using advanced darkroom techniques and even has multiple versions of the same image out there. There is a great Ansel gallery in Santa Fe that has many original prints of same images he did over many years as he gained new darkroom skills. It is really neat to see the different prints hanging next to each other.
Back to today and digital imaging. Most serious photographers shoot in RAW format so that they can make adjustments in the computer later. When a RAW image is first opened in the software, it is often a very dull image because there is no saturation, white balance etc applied to it. SO it is necessary to make adjustments. In many cases, these adjustments are done in photoshop.
Below are 2 versions of the same image I took last fall. The first is the RAW image and the second is my finished version(processed with Aperture and Photoshop).
I look at it this way: the RAW image is the negative and the post-process software is the darkroom. Now, of course there is another question around all this and that is are you striving to present a realistic image or a manipulated piece of graphic art? In my case I am usually striving to present it as it looked when I shot the image (although I admit I sometimes try and make it "pop" a little). If I stuck a giraffe in the above image, and presented it as a picture of Crested Butte, that would be unethical... :)