I currently use (drive):/projects as the location for the all projects I work on and (drive):/build for executables and installers. The build location is set by out IT, otherwise LabVIEW builds get seen as viruses.
Within Projects I usually use Code, Documents, Prototyping, Test. With the project code under the Code folder; Documents is requirements, design, etc; Prototype is initial design and testing code; with Test used for unit type testing.