"1. Set up a media server. There are many, many ways to go about
doing this. There is the old tried and true file server approach,
using either NFS or Samba.
"However, if it's only music you're sharing, you probably want
something more like Firefly or Tangerine, which can share all of
your music with the other computers and devices on your network
with DAAP (this is the same music sharing technology iTunes uses).
Most Linux music players provide this capability as well. If you
want to access your music from anywhere in the world, you could set
up Jinzora, which is a web based music server...
"2. Set up a download server. Centralize all your downloads to
one Linux powered server. Get your Usenet downloads with HellaNZB
or SABnzbd+. Get your torrents with Transmission, Vuze (formerly
Azureus), TorrentFlux, Deluge or MonoTorrent. All of the software
mentioned in this section has a web interface of some kind."