The lack of a network connection drastically reduces the convenience by forcing you to disconnect your USB hard drive to copy stuff onto it and reconnect is one of the reason I did not pursue to purchase WDTV. Also, WDTV does not even include a HDMI cable.
Considering my budget of <$200, Mvix Ultio satisfies my viewing dream. Ultio package includes HDMI cable - which itself is worth ranging from $10 - $50 - depending on where you buy it from. Very easy to set up, takes 5 minutes to complete all configurations and installations, and its ready to play.
Awesome features includes supports for ISO, MKV, RM/RMVB formats. I'm loving it everyday!