Photoshop - self-explanatory I believe. Nothing is as powerful when it comes to making your textures. Yes, there are others that will do the job (and I don't want to get into a big argument about PSP vs Photoshop vs Gimp vs whatever) but it's a professional tool, and will do whatever it is you need doing, even if you don't know you need doing it What I mean is as you get more into the game, you may find yourself needing something that you just don't have, should you have decided on other software. I'm willing to bet that Photoshop will have it.