a4quattro:
You'll need iTunes running really. Those NAS drives with an "iTunes server" just show up as a shared playlist down the left-hand side, in my experience.
Sonos will work in the way that you want. i.e. just a standalone NAS running without a computer.
You can use the iPod Touch/iPhone as a remote for the Sonos but also with iTunes, although it looks but iTunes running on a network somewhere.
http://www.apple.com/itunes/remote/
An alternative suggestion would be a Mac Mini or Apple TV running iTunes pointing at a NAS. Yes, okay, the Mini is a computer, but it's tiny, silent, cheap, lovely and can essentially just be your iTunes computer.
It can be set up to rip automatically as soon as a CD is inserted, so you don't really need a keyboard or screen once setup. Just control the music with the Remote App on iTouch.
Yeah can't be much help here, since my Mac is on all the time and acts as a server, with the music stored on network drives. From my research it does seem as if 'itunes servers' (as advertised by Lacie and QNAP for example) aren't iTunes servers at all, in the way that squeezeserver and twonky are.