This may seem facile for me to say, but for just a little more, you can have a Mac mini media server that doesn’t run on the dippy Windows Hone anything, which is almost guaranteed to be stunted and annoying. The mini solution is versatile and powerful.
That said, Western Digital makes a very cool network adapter-cum-media player for USB drives, to turn nearly any mass-storage device into a media server, with HDMI. I wanna try it out on a Drobo sometime.
Finally, I can see that, in the not-too-distant future, some Core 2 Duo Macs will start needing to be retired as primary workstations, and I would anticipate some of them being ready for repurposing as media servers. Similarly, one could buy a used machine for that purpose.
The right form factor and cost for this idea is really the Apple TV, which is such a sad and crippled piece of hardware, I stopped recommending it a while back. I’m hoping the recent price drop signals inventory clearance, for a proper model to arrive before the shopping season.