I just watched a GIMP video on youtube. I've got a headache! As a PS CS3 for Mac user, I'm astounded at how clunky it is.

If you're having problems with the idea of layers, you may not be ready for the next steps in photo editing. Maybe it's time to think about your photography philosophy?

Some people put a heavy emphasis on layers because that style of editing is suited for the end product that they want. As a photographer who personally believes that photography should be about recreating life, and to an extent a visual truth, layers aren't as valuable. So I would think about what the end product that you, as an artist, want - do you want heavily stylized photographs with lots of editing, or do you want to take the images that you've taken and tweak the color, cropping, etc to enhance what you've already taken?

Both tracks are equally valuable but they produce very different results. It's up to you.