Instead of using Photoshop, why not give Apple's Aperture a try? Aperture is designed more for post-production work for professional photographers, letting you cull through shoots, enhance images, manage massive libraries, and deliver stunning photos.
Watch this video tutorial on how to edit multiple image versions of your master in Aperture. With Aperture, you can use one master image to create as many different versions of it that you want, each with its own set of adjustments, and you can reate all of these variations without ever having to duplicate, rename and keep track of multiple copies of the same image. Edit multiple versions of your photos without ever touching your digital masters.