I have a HP N54L Microserver. Bought for something like £70, brand new. It's got a few WD Red drives in it, running Synology OS. I have Plex running for all my streaming needs to my TV/iPad/Laptop etc (all done without HDMI), an in-built Download client, and backups for my laptop/phones via Time Machine (running a Retina Macbook Pro). Added native app support (on iOS & Android) and I can access, upload and download from my server anywhere in the world, even from my phone.
Cheap, reliable & functional. Frankly, i'm not sure what else you'd need!