I always recommend Google's free Picasa. It's intended for beginners, is very easy to use, and while limited in what it can do, no curves or layers for example, it does what it does very well. I don't like the way it wants to reorganise all the photos on your hard disk and help you post them to Google's special photo services on the web, so I just told it not to do that in the settings. I now use quite a variety of different editors when I want to do complex things. I nearly always shoot RAW plus JPEG because the circumstances when I'll want to do careful processing from RAW are too unpredictable. Picasa has limited RAW processing powers, so when I want to do that I'll often use another more sophisticated editor. But 90% of my images need no more than a bit of cropping and tweaking of the JPEG image. I've been surprised to find that Picasa is so good and quick and easy at that that it still does all the processing on 90% of my images.