After I had created the base mesh, I did just a little bit of deforming in ZBrush.
Deforming in ZBrush
When I was content with the shape, I went back into Max and did some modeling by using the Graphite modeling tools and the retopologizing technique. I have experience with Maya, XSI, ZBrush and Topogun too, and in my opinion it's better to use ZBrush or Topogun for retopologizing because the polygons will snap on the surface very well.
Final model, render to be rendered
Textures and Materials
I used the mental ray Arch and Design material and SSS system for this project, as they are very good at portraying metal materials. The Arch and Design materials have some good preset settings with which you can create all sorts of realistic materials. These are a good starting point from which to create your custom setups.
I also used an HDR image in the reflection map slot, which helped greatly in achieving realistic metals instead of relying only on the environment reflections.
The Arch and Design materials dramatically increased the render times, but I think the end result was worth the wait.
For scratched and weathered parts of the armor, I painted alphas with some other dirty textures in Photoshop.
For UV unwrapping I used the UV Editor in 3ds Max and most of the textures such as the face and patterns were created in Photoshop.
Some of the materials and textures used