Well however many times its been posted, a refresh is always good.

Well bump maps and normal maps are almost the same thing really as neither of them distort the geometry in a physical way like a Displacement map does. Normal maps are regarded as a super bump map as it uses the direction of surface normals of a model to give the impression of it being bumped, they do look better than your standard issue bump though for sure.

Bump maps and Displacement maps are only similar in the fact that they are coloured black thru to white ( values 0-255, black being 0 and white being the uppermost threshold of 255 )

Bump maps work pretty much for anything, and can be used to a good effect on long to medium work but can the closer you go the more they will finally give way. But that is where you decide whether or not you are gonna need a dis map to show of the surface of the model is actually physically bumpy. Bump maps are reliant on light angles to show them off well and from a certain distance as Ive already said.

However displacements also can be disadvantageous, as UVs need to be good -seriously good if using them on hardsurfaced models. I have had many discussions with CG supervisors on them as some prefer them some dont. My Supervisor right now would prefer not to use them on hardsurfaced models and stick with bump maps or have the models with the detail there. At the end of the day you cant beat the geometry - Avatar used geometry for all the facial expressions of the characters, as dis maps caused problems when animating (swimming and blurred textures) .

hope that helps for now - gotta go out !!

Jay