So I've been asked whether Photoshop or Painter is the right call...Well, it really depends on what you want to do. Both have advantages and disadvantages, and to work around these, I actually use both.
Photoshop does all the photo stuff great, such as color correcting or dodge and burn, and it can make intricate selections in many useful ways. The healing brush and patch tool are also nothing to sneeze at. Photoshop also has the advantage of being the popular kid on the playground, so there are brushes and filters you can add from third-party vendors.
Painter, on the other hand, is definitely made with the artist in mind. This is a fantastic tool when you need a piece of analog-looking artwork without the mess (and with multiple levels of undo). You can paint in watercolor, oil and acrylic, or draw with pencils, crayons or pen & ink, just to name a few. And the great part is, it actually looks like you've painted in watercolor, oil and acrylic, etc. I also like being able to rotate my canvas as I work, just as I would be able to had I actually been drawing on real paper.
Here's how I've been working lately:
I'll draw my sketch by hand (on real paper with a real pencil), and scan the sketch into Photoshop. In Photoshop, I'll make any rearranging/resizing changes that may be necessary, and save the changes as a .PSD file. Next, I'll open the file in Painter and do whatever painting or drawing I'm planning on doing, and save the file in all its layers as a native .RIF as I go. After I've finished in Painter, I'll drop all the layers (like flattening in Photoshop), save the file as a .PSD, and open it in Photoshop. There I can correct any colors, or convert to whatever color profile I need to. I've also started using grunge brushes in my work which I'll apply at this point (please see http://www.the-rots.blogspot.com for some grunge edge examples -- all of the color and pen & ink has been added in Painter). From Photoshop, I can save the file however I need to (there are about 16 different types of files Photoshop can save as) or use the nifty "Save for Web" feature.
Photoshop or Painter? It depends where you want to go with it.