Another use of noise (this is something I use all the time) is to break the repetitiveness of tile-able textures. At its simplest, you can use this method to texture a large area (say a building's firewall or an entire road) using maps that would cover only a small portion of that surface, but without having them show any visible tiling. The trick is to mix two copies of the map (one of them with slightly offset coordinates) and mix them using a low-frequency, noise-based mask. This way, you get a vast expanse of non-repeating textures with the close-up crispness of high resolution detailed textures.
In Fig.04 you can see how I used noise functions (and vertex color) to add interesting, geometry-dependent and seemingly random fine details to the Specular, Glossy and Bump channels of the table's metal materials, using mainly low resolution textures and no UV unwrapping. I also blended two different materials in order to give the final metal a separate coating, a bit like a car paint mat. You can see that although the Scratch map appears very tiled in the preview, it comes out looking a lot more random, once it has been mixed and masked with noise and (black and white) vertex colors.
In the same spirit, I often try to enrich my materials by adding an additional layer of Specular or Glossiness via a separate map that has nothing to do with the diffuse or other channels and is positioned on the model using different UV coordinates. It adds a lot of realism and is also a great way of hiding seams in the diffuse or the other channels. In Fig.05 – 06 you can see how I added the same generic Dirt/Scratch map to both the floorboards and the wooden table, giving it an extra touch of realism.
Several people have asked me how I did my curtains (Fig.07). Well, this is Max's good old Cloth modifier, which can work wonders provided that (and here lies the secret), you give it a lot of time. Simulations, especially if you are using low-quality settings, tend to be very bouncy. Therefore it is important to up the settings (the generic heavy preset, for instance, works very well) despite the higher calculation times, to make sure that Self-Collision is on, and to let the simulation run until it really settles (which can be over as much as 800 frames – easily an overnight job, since cloth is single-threaded – no pun intended).