The ones that are index files can be safely deleted. The Div X Folder and the Narration Folder, if they are empty, can be deleted.
Auxialliary Files can be deleted within Studio under File/Delete Auxiallary Files. Studio will put extra files it needs for render in the folder where you tell it to put the rendered file and..when you render, you had a drive and place selected where auxialliary files would go.
For example, I have designated Drive F for my auxilliary files, so I have a folder called "Render" and this is what is inside.
See here where I designate F for this.
ImageShack - Hosting :: 01182008132709nf9.jpg
and here the contents of the file.
http://img101.imageshack.us/my.php?i...8133919pw8.jpg
I could safely delete all these files now if I wanted.
Then my rendered files were specified to go to C Drive. So my rendered file is really the only file I need. Everytime you do stuff in Studio (and other programs do this too), they leave index files behind but these are not needed.
Where you will run into trouble, is if you want to edit something later, and you have moved your "source" files. Then Studio will prompt you to repoint. I've done this without thinking

and sometimes I can't remember where I moved things.
I've just got a new computer and I've promised myself that I will be careful and place things properly to start with - we'll see how I do.