I love Photoshop and Illustrator, but I don't like drawing in them. Even with my digitizing tablet, I just don't have the same control over input as I do with paper and pencil. I'm not alone in this -- it seems like many (if not most) illustrators who have to work or want to work digitally still rely on paper, pencil, pen, and scanner to get their basic image ready for digital work. But then the really fun part of digital art can begin -- you can try so many different ways of coloring in the image, playing with textures and brushes and various ideas on how to really make the basic image better. You can do the same thing with paints and pencils and markers and such, but it would take a lot longer. Sometimes I use the digital tools only as middle step -- as a way to experiment and come up with the final coloring, etc. -- before making an actual painting. Sometimes I intend to have a digital finished product.
An example from my sketchbook:
2) I cropped and sharpened it
3) I tried a varity of color treatments (some of these are unfinisiehd to save time, but you get the idea): translucent brushing, bucket-fill, blending with background texture, and vectoring in simple color blocks.