After a miserable time trying to get 720p and 1080i/p content to stream wirelessly to my HTPC (from my NAS box), with Wireless N routers and adapters etc and realising that I might have to run a cat5 cable from the router (upstairs) down to the living room.
However, after doing a small job for a client and seeing some Ethernet over Power adapters, I went out and got a pair of Devolo dLAN 200 home plug adapters.
All I can say is - WOW! It works beautifully. Only real catch is that they want to be plugged into a wall socket rather than an extension (but it does work), and they're quite expensive. I haven't measured actual speeds, but all my HD content played back flawlessly (720p, 1080i and 1080p).
I chose the Devolo over the Netgear equivalent as the Netgear adapters are much bigger and foul adjacent power sockets.
Other good point is no need to drill any holes or staple cables to the wall which keeps the wife happy!
Yippee!