For organic models - like humans and animals and monsters - my first choice nowadays is the tritone shader (textured variant; keeps the underlying texture). I simplify the settings negating reflection nodes, toning down or disengaging specularity and sometimes killing off displacements and bumps. On other occasions I specifically put noise on bump channel. I use coarse line values between 0.5 and 0.7 and fine line values between 0.5 and 0.7 as well. F.ex. the thief/rogue woman on page 13 was done with coarse line and fine line values of 0.68 (too much - I would lessen the shader impact if I was making the image now). One white infinite light with intensity values of 125-140% is usually adequate (since most of the lightning comes from ambient channels) for my needs, but sometimes I use a second light for more dramatic effect. Light placement has an impact as well. For the main body of my illustrations I go for placing the light close to main camera.
I have no fixed settings - the settings live between images and it is common to turn off shaders altogether sometimes or to do a final render with different shaders on certain material zones. A common trick is also to lessen the impact of texture by 25-45% and set a diffuse color close to a average tonal value of the texture.
When I'm done, I do the same thing with a dual-tone shader and select the low backlight variant of the black/white shader. It gets me the b/w outlines. That render doesn't actually need to be very good since it's pretty easy to just draw missing lines in postwork.
I almost exclusively use P4 renderer disabling bump maps and shadows. At times I also make a firefly render with high AO levels and then do a slight overlay of that render on top of other layers in postwork - it gives nice soft shadows on armpits, creases etc.
Then again, on architectural models Olivier's shaders don't really work that good. Same goes for organic items with lots of alpha-mapped planes (like trees with leaves). When doing those, I resort to other means.
That would actually be pretty nice since I mostly find myself liking the postwork part of the process best. At times the 3d part gets boring - especially when dealing with Poser quirks.
Here's an example of a scene from around a month ago. I'm still not happy with it (ie. this is not going to be final version), but this has a totally different approach than when making humans (shader-wise, that is).