When I use bump maps with my figures, it doesn't look any different from when I render without a bump map. Is there any point in using bump maps with figures? In this image the bump is set to 100% on the right, but it looks exactly the same as the no-bump image on the left. Why is it so?

Just wanted to add that I do use bump maps with other props etc. and it works fine. I'm just not sure what differences I'm supposed to be seeing with human figures.

With human figures, the effect is much more subtle, and unless you're using them for veins, muscle tone, or other prominent features, like scars, then you're not going to notice much differance. :-)

The best way to see a bump in practice is to make a copy of the texture you're using, make the whole thing black, but put a smallish square of white in a prominent position, like on her cheek or chin. Render and look for the mark. Also, remember that the bump map is not actually adding bumps, just the appearance of bumps, so the light source is also important. You really need shadows turned on and the light at an angle to see the effect fully. Just be careful with faces .. although the effect is reasonably subtle, skin can look like orange peel if bumps are over-done. If you're not squeamish about nudity, you'll see the most extreme effect from bumps if you use a map on the model's buttocks. Bend the buttocks quite a lot (stretching the mesh), then render with a strong light source. Eeeek! Digital cellulite!