just regl’r ole photoshop- I have CS5.1 which I bought when I was a student, so I got a discount on it, but I’m not sure how much it costs now (I think you can get bundles of programs together for less?) what I do encourage you to look into if you’re a photoshop user are Kyle’s Brushes; I love them so much, and the ‘ultimate megapack’ is absolutely invaluable