Have you considered a Nintendo Wii? They can be modified to be an all round media centre. They'll play video files from SD card, USB device or disc, and you can still play games. The only drawback is that its not HDMI although you can get something to convert it:http://www.amazon.co.uk/Wii-HDMI-Converter-WII2HDMI-CONVERTER/dp/B007PY3ZPG
I've got one for Sale
on here, I'm not pushing a Sale
, but you're more than welcome to pop by and see how it works.