Quote - feel free to yell at me but if you have zbrush what do you need photoshop for ?

One word: ZApp Link.
Well, I guess that's not exactly only one word. ;-)

If you don't know what that is, it's a plugin for working between Photoshop and Zbrush, and transferring textures back and forth, while working in both programs at the same time on the same textures.
It works for Painter too, I think, and probably for GIMP and maybe Paint Shop Pro too.