PowerLineEthernet (PLE) is offering fantastic speed of 200 Mbit/s, or equal to full-duplex 100Mbit Fast Ethernet. This is more than enough for streaming any of the current HD formats.
The new 200Mbit products are shipping as of next week. And, if you're interested, make sure you're getting a product that complies with the new standard, not the old ultra-speed one (84 Mbit/s). You can spot the products by seeing HomePlugAlliance AV marker on the product packaging.