In my opinion, you just can't beat Adobe Photoshop. It is powerful and multi-purposed for designers, photographers, painters, and many other artists and professionals. The program is fully functional with a Wacom tablet, which helps bring a whole new dimension to your artwork. If you are new to Photoshop, I would definitely recommend watching a lynda.com tutorial on how to get the most out of it. There is a lot you can do, but you have to know how. Best wishes!