The viewsonic VMP74 is exceptional value for money. It will play just about any format you can think of direct through your tv as well as having internet browsing and direct access to you tube and others.
There is no hard drive but one can attach a drive or usb easily through the many connection points available including network.
This would get 5 star except that the ability to connect wirelessly is limited by compatable wi-fi dongles.
For £60 or so easily beats the likes of Western Digital and boxee for home systems.