Best advice I can give you, grab an external HD. Don't go to walmart, it's all over priced. Best 'bang for your buck' will be amazon. This is mine. I just edit what I need to edit for the time being and keep the edited photos in the same folder as the unedited photos when I first uploaded that batch of images. This way, I still have every image incase something goes wrong. When I'm done, I drag it over to the external HD and rename the folder.

For example, took pics of a grad party a few days ago. Went home, did my editing, uploaded pictures to my website, renamed the folder "Grad Party 6/11/09" and dragged it over to the external HD. It's saved there, so if the people want more edits, I just tap into the HD and edit some more...

Hope this helps!