Help Selecting a NAS

Hi Guys

I'm new to the forum and am hoping that I can get some help selecting a network attached storage device. I've trawled through several review sites, and I can't seem to find the right fit.

Here's what I want the NAS for:

Sharing Music
Sharing Video
Sharing general files.

Looking through all the various device descriptions this seems pretty simple, here’s the requirement I'm struggling with:

I need to be able to map the NAS as a network drive in windows (XP, Vista and 7) as well as assign the NAS a static IP within a non-standard range (my network is setup is somewhat unique).

All the Netgear and Buffalo drives I've seen seem to require use of propriety software, which I'm keen to avoid. Essentially all i want and need is a network file server (on a smallish budget)

Having an inbuilt torrent client would be advantageous but its something I could live without.

Hope you guys can help!

Thanks in advance!

Ahmad