The material room is the one feature in Poser5 that will make stay with it, at least till Daz Studio will offer something comparable. If I understand correctly, Studio will contain one or more predefinde shaders, but with Poser 5, I like to use custom material shaders individually twaked to my images.
Actually 3Delight, the renderer Daz Studio uses offers something even more powerfull than P5, fully programmable Renderman shader, but working with that is a programming job. May be I will try that. (Note: You can use 3Delight with Poser, thank to Stewers sripts)
The material dialog in Poser 4 is only easy to use, because it can do nearly nothing.

Stefan