I have to say, I love using the layers as transparencies and reducing opacity so that you can still see the layer below it. If I ever figure out how to do THAT with paper, ink, and stamps, I'll probably lose ALL other hobbies, because it will become an obsession. lol
Anyway - I take credit for none of the images - they're all brushes downloaded from various sources at deviantart. If you're interested in one, let me know and I will share the info.