A minor note I feel obliged to post after previously recommending Picasa. If you're using it to handle Nikon NEF (RAW fomat) files, be aware that its handling of the files is seriously sub-par. The above is an example of using Picasa's internal NEF reader versus Adobe Photoshop CS. It seems that it's not always great at translating the NEF file into screen images in terms of color balance and contrast. Over the past two weeks I've felt like I'm doing a poor job with exposure, but today I realized it's the changeover to Picasa that's been messing me up. (I don't have end-to-end color management, yet.)
Note this will not be an issue if you shoot JPEGs, which most casual photographers will be doing. In that situation, your RAW file is being converted within the camera to the final JPEG.
