I have a small home network (2 boxes and a hardware router connected to a 6 port hub).
One is a multi boot system:
Slackware 10.2 (2.4.x kernel), SuSE 10.0, Slackware 10.2 (2.6.x kernel), Debian, and Win 2000
The other is my file server running Slackware 10.2 (no X) with the following services:
You could just as easily set up both machines as "servers" running the same services (maybe not the last 2).
So long as neither box automounts the other's shares, then the server does not need to be running all the time.
NFS is easy - http://nfs.sourceforge.net/
ssh is just a matter of enabling it on the "server" then logging in:
SAMBA is more involed, but read the well commented samba.conf-sample file in /etc/samba and the HOWTO.
On my system, my server has no mouse, keyboard, sound, and a very cheap vid card.
I do everything from my client box.