Cool Maya,,
You have some real nice software. Photoshop is superb. ZBrush is an amazing program as well, yes it does max out the processor but its worth it. I have'nt noticed any harmful effects. I realize that it renders on the fly and believe that to be the reason for the processor use, I have noticed that my cpu settles down a bit when there is no active 3D object in edit mode. Pushing thousands of polygons around with instant feedback has a price. http://www.talkgraphics.com/images/smilies/biggrin.gif

There is a ton of neat stuff you can do with photoshop. Did you make the leaf brush yourself or was it included?
I have some cool custom brushes, one click trees, clouds, bushes, lightning and such.
Its Fun...
http://www.talkgraphics.com/images/smilies/biggrin.gif