Wow. Lots of information in this thread for sure. I've done a little of everything. In the beginning, I organized it by splitting it all up cause it was just for me. But then I became a CT, and started organizing it like Kimberly does. I have separate folders for each designer within the store they are from.
For my commercial use stuff, I do like Rebecca, and organized them by Bows, Frames, Clips, etc. I just make sure the Designer's name is on her product before dividing stuff.
It's still so time consuming though isn't it? I need to hire a personal assistant to just be in charge of organizing everything on my computer so I can just worry about designing and scrapping.