I am of the opinion that, for digital painting and whatnot, photoshop is a good one to use. Granted, you can digitally paint in ms paint and get some ridiculous shit, but photoshop is up my alley because I already know all the shortcuts. Use whatever you're comfortable with in my honest opinion.
I have before, but it's a very rare occasion. My friend tried to sing...yeah, I fell off a chair and rolled on the floor.