I'm on a Mac, but I guess it applies to Linux too, since I'm using a command line. When I write web applications, the apache user (which is _www on a Mac) has to be able to edit files as well as me.
Also, I don't want to set this for every single file or folder, I would like to set up the root folder and then I and _www will have access to every file inside this root directory.
As it stands now, I have to use chown or edit with sudo to accomplish things.