I guess I want a better explanation on what is the main differences and the significance of the having each files.

Yes, I understand now. I think that you want the question to be re-opened so I am all in for it...

Wow... Eliah, that is just about the most detailed answer I have ever received on a stack exchange site... I am definitely accepting this answer and up voting for the descriptive and vivid content. I hope askubuntu does become a huge library of specific questions and problems on Ubuntu. Good luck to you.

@EliahKagan thank you very much, nice to know every once in a while someone is on your side.