PowerlineHD and HDMI audio
I got my PowerlineHD equipment today – its certainly not Gigabit, but iperf reports around 90mbps and NFS transfers go at about 6MBytes/sec, so faster than 54G wifi can manage, and fast enough to stream SD video for sure (not tried HD yet).
The one downside is that it seems to be interfering with the radio in the kitchen, although the wireless keyboards and Bluetooth headset and phones are fine.