I organize all my work for a client within one folder named for that client. CLIENT FOLDER will, in turn, have folders named for each project as well as a folder containing that client's main assets (logo, frequently used images, catalog, etc).
In Studiometry, I like to use a project's Files window to link to the main Client Folder and the Client Asset Folder as well as folders and files specific to that project.
It would be nice if I could have the Client Folder and Client Asset Folder added automatically to any new project. It could be that a Files window is added at the Client level and any files or folders added there would be attached to the client's projects.