eBuyer has their next HP micro server promotion up. Its a slight upgrade over what I think was the N40L (Could be N45L). The price is currently £209 with a £100 cashback (you'll be waiting a month or so for this).
The specs are pretty basic, but this is ideal for my intended purpose of it being a NAS box to share all my videos and music across multiple devices. I haven't bought any upgrades for it as of yet. I want to experiment with it first as it'll be my first NAS box. The 250GB hard disk should suffice for the mean time until I am ready to use it properly. Its interesting to see what people have done in terms of running the OS off a flash drive on the internal USB port or their set-ups with RAID arrays.
I'll also need some sort of Dynamic DNS service as I'm on a residential Sky broadband line with a dynamic IP. Free ones can be had from www.no-ip.biz, but there is also dyndns.com which is $25 a year. Then again with the O2 purchase, Sky has been hinting at rolling out a static IP address to some customers. My guess is probably at an extra cost which is fair enough as it isn't a business service I guess.
Other concerns are noise. I want it to be dead quiet as its going to sit in the living room. I recently upgraded my Shuttles graphics card (a whole different beast) and it's noticeably louder these days.
http://www.freenas.org/ is looking like the OS of choice from what my colleague suggested.
From what the site says it looks pretty versatile which is what I need running a variety of OS's in my household.
I've not used a Windows server in a long while now, but it might be worth a download of the trail version to have a look. I've heard some good things about Windows Server 2012.
Link to the product is here: