I know a lot of artist are uncomfortable with "copying" - but I've always seen it more like training. Recently the class I've been taking on the side at my job at the animation lab - assigned doing a breakdown of a master's work. I went with two of my favorites - Tom Oreb and Marc Davis. I did both of these studies with Photoshop. I was going to add my own version of the Infamous Red-head from the "Pirates of the Caribbean" ride and a turnaround of the Tom Oreb's (I think it's Oreb's) Briar Rose - but once again I had more work going on than I thought.