I voted to close this.. it is way too opinion-based in my opinion. :)
For what it's worth I use a directory titled "Working" for construction files.
Then a directory titled "Images" for final images to be used.
All my projects essentially have the same directory structure....
- [Client files]
- [Build] (directory if web project)
- [Older] (Backup directory of previous project file iterations. Basically I send the client a proof on the 10th.. they get back to me on the 15th. I copy the file from 10th into this directory, then make changes on the original file from the 10th. This allows me to revert to a previous proof if it's ever needed.)
Within the various directories you can add additional subdirectories if you want. You can do
Working -> Raster or
Working -> PSD, whatever. But by putting it in the "Working" directory I know it'll be the live, unflattened, editable, file.