I first learned art on a traditional medium, but once I started using photoshop and a tablet and I saw how realistic you can make your results I just use photoshop for all my digital renderings. I still do sketches and such on paper for concepts if i am away from my comp, but I enjoy all the benefits that come with the digital medium. You can easily fix mistakes, it costs less in the long run since you dont have to keep buying paint, pencils, paper, canvas, etc., and when youre finished there is no mess to clean up