Central Server Network

Hi guys!
I want to set up a server so I'm able to administrate users,computers
and shares easily.

I post this to get some information about the beginning of my project.

So, the user administration I can handle with a PDC, I think. Thats not
a big issue but the rest is difficult.
I want to install the programs, which every client machine is able to
run, only on the server. Short: I want to make an application explorer
(or something like that). Do I need a 1Gbit/s LAN or could I use my 100
Mbit/s LAN? (There are 6 Computers in my network)

The client machines should have a very clean GUI; there should be only
some icons (or this App Explorer) and thats it. The Configs and so on I
want to make with the server. Is there a linux which is made like my
ideas or similar like them?

OK I think thats it
thx in advance
David