By default, whenever an application is installed in OS X, it gets dropped into the /Applications directory.
At the moment I have 85 items in /Applications, and if I want to open up a particular application from the /Application directory I have to do a rough guess as to where it is located in the Finder's list and then perform a manual linear search until I find what I want. It is even worse when I can't quite remember the name of the application, so I have to do a linear search of the whole directory. And forget about it if all I can remember is the type of functionality I am looking for, but can't remember any part of the name.
In Windows I solve this sort of problem by manually re-arranging the short cuts for the start menu into hierarchical groups based on functionality. This is easy to do in Windows as I am only moving short cuts and not the installation directories of the actual programs. However in OS-X what is displayed in the Applications section of Finder is the installation directory, so there is no easily manipulated layer between the what the Finder displays and the actual directory.
As a concrete example of what I want, currently I have in /Applications:
/Applications Address Book.app .. /Adobe Photoshop CS3 .. .. (30 other entries) .. iPhoto.app .. .. (20 other entries) .. Photo Booth.app ...
But what I would like is
/Applications .. /Photo /Adobe Photoshop CS3 iPhoto.app Photo Booth.app ..
So the big question is how to achieve this. Can I create the sub-directories in /Applications that I want and then just move around the app bundles and directories as I see fit? Or is there a different (Apple) way of achieving what I want?