Ok say you work on various Macintosh systems one at home, another at work and a third at school. In order to have the same preferences that you have on all 3 computers that you have at home you would have to either a.) transfer every single preference file to each computer(not pretty it gets messy) or b.) use remote login here's simpler idea in theory:

What if you could have different profiles, one for home, another for work and another for school AND you could easily switch between them, thats the essence of user profiles. OS X would create one file (most likely a package) that contains all of your preferences not only your UI prefs but your application prefs as well. In order for this to work applications would have to store and access their preferences from a localized area and maintain distinct preferences for each profile. You are most like likely thinking: "Isn't that the preferences folder?". To some extent yes, but no its not the same. The preferences folder only keeps the preferences for one user you cannot switch those preferences to the company preferences (or profile in this case) and back with out replacing multiple preference files. If you could have set up mulitple profiles (roughly the equivalent to multiple preference folders) then switch between easily then this would allow you to merely load your home profile onto your work and school computers, then when you are done switch back to your corporate or school profile.

This idea would not only help you switch between preferences on any computer by copying your user profile/workspace(s) onto the machine, but in case of corrupt preferences you can switch back to the default profile/workspace and continue working (or switch to a back up profile/workspace). this concept is very similar to how Photoshop allows you to create and load different workspaces with different preferences.

Each 'workspace' or 'user profile' should be a single packaged file containing the preferences folder under the ~/library/ folder. A preference pane would need to be created that allows multiple profiles/workspaces for that same user to be loaded and unloaded. Users can change their profiles/workspaces at the login dialog or this preference pane; Name user profile(s) or user workspace(s)