There has been allot of back and forth on whether to shoot RAW format or JPG format.  Those without the RAW capability always shoot JPG. However,if possible,  using RAW is far superior because it retains the MOST INFORMATION POSSIBLE FROM THE SUBJECT  in image file. I know many say the only picture that is correct comes directly from the camera without any processing. This is incorrect because of these two important items:

• The RAW image is NOT accessible to be viewed. It is only a series of floating point numbers representing the luminosity of the RGB (red green blue) of each pixel. 
• So the camera must process these pixels and make a JPG  or output as RAW and have the photoprocessing software create and image that can be viewed.

This processing, either internal in the camera or in the photo processing software, leads to LOSS OF INFORMATION. Once the detail of the pixel info is lost, it is never to be regained. The following shows an example of two histograms of the same image, one in RAW and one in JPG:

The top histogram is from the RAW and the bottom histogram is from the JPG.

It is clear that the bottom image has “lost” data as compared to the top one. This information is never to be regained.

There is a very good article about this whole concept and you can click here to read it.

I find it disconcerting when there is an expectation that the “only good image” is the exact image from the camera. There is always processing. One cannot “see” the image from the CCD, it is only a matrix of binary numbers. So I take the stand that it is MY vision that sees the subject. I want to conform the information from the camera to that vision. The following explains what I am trying to do:

“Not all photos need to contain every tonal value the photographer observes or that exist in a scene. Some tunes are best played with a smaller range of notes. One technique often used by experienced photographers is to first record all the tones possible and then edit out, or obscure some later. Indeed, some of the best photographs reveal some of the tones while hiding or darkening others, thus guide the viewer’s eye according to the photographer’s artistic pleasure, or even whims. That’s the difference between the objective exposure, which strives to gather and record all the values and colors in a scene, and a subjective, or expressive exposure, which manipulates tonal values and color for certain aesthetic ends. If you ever have a chance to look at a master photographer’s negatives, such as Ansel Adams, you’ll see a considerable difference between the original negative and the resultant print.”
This is from an article in Shutterbug magazine “Objective And Subjective Exposure“
by George Schaub

I use this technique to ‘fine tune’ the image to my vision. It is working great for me. One of the Photoshop plugins I use is NIKsoftware’s Vivesa click here for more information