HI if you want an IDE for programming shaders, totally free, and very interesting... you can dowload this:
http://cg.in.tu-clausthal.de/teaching/shader_maker/index.shtml
I think render monkey, it´s better becuse you create the "materials" like in a 3D suite, it´s more visual, but for me, whit my VGA card, don´t works... something about Nvidia card and OpenGL, I suppose..