What are the core packages for a desktop's Linux desktop distribution

Hi everyone. As a Hobby I want to build a Linux system from scratch. I know there is a lot of information on the subject but I am not absolutely sure about the "real" minimum of packages that it would require. Want I want to build is a system that run gnome, openoffice, firefox and that can provide a basic set of command line tools like "ls" and nothing else. I know there are hundreds of interesting packages that could be added to this list. But for the moment I don't want them. I trying to create something like XP home and I don't want more power than that.

Here I provide a list of want I think should be there. Please help me fill the blanks. By the way I am not a guru so please try to keep your answers simple and remember just to provide me with the packages for these tasks nothing else unless it will be nice to have.

Kernel

Of course I need a kernel

File System

I need some kind of file system like ext2 and a mean to parbreastion and format this file system. What are the most basic packages that will provide this?

Internet

I need to be able to use Internet access both dial-up and DSL only for client purpose. I don't need apache or any other server. What are the most basic packages that will provide this?

Share Documents

Some way to share file with other will also be nice. Maybe NFS of FTP. What are the most basic packages that will provide this?

Sound

What are the most basic packages that will provide this?

Xorg or XFree86

I only want this to be able to run Gnome. What are the most basic packages that will provide this?

Command Line Tools

I don't want anything fancy here. Just the equivalent to DOS something like ls, cp, format and ping. What are the most basic packages that will provide this?

Gnome, Firefox, Openoffice

I want to run the core of these packages. I know that exist million of packages designed to run on gnome. But I just want to be able to run openoffice and FireFox nothing else. What are the most basic packages that will provide this?

Security?

I need to be able to do some basic file level permissions; I think that the avility to create users and limit access to the file system files is enough.

Package Management

I want to be able to install already compiled applications that the user will download from internet and that will not be included on this minimum system. Maybe gzip is enough as a distribution mean but I accept recommendations!

Graphical Administrative Tool?

I want a package that runs on gnome that provide access to the basic configurations like TCP-IP , user creation and file permissions. I think gnome already provides this but I am not sure.

And that is all. If you think I need something else is missing please let me know but remember that I am not interested on power just in the features I just mentioned!