I'd be interested to hear what others are using for playback these days - I realise the market is saturated with small Android powered dongles and other devices, as well as the more hardcore stuff like homebuilt media centre PC's.
The backbone of my setup is a Synology NAS with 1TB of RAIDed storage. Synology is a good choice in that you can install packages on it such as SABNZBD and let it take control of downloads for you - it even emails you when it's done. It's a better choice IMHO than leaving a PC on all the time as it's a) already always on as it provides NAS capabilities to your home network and b) uses less power than most desktops.
For me, I have previously used a Popcorn Hour to stream media from the Synology to my TV across my wired network. Nowadays I am using a combination of a Boxee Box (when I want to use my projector) and a Raspberry Pi (when I just want to watch something on TV).
I think it works pretty well, but would be interested to hear what others are doing, especially those of you who have gone down the totally silent route for a media streamer (whatever it may be).