Best Hdmi Stereo Receiver 2009 Xbox 360 W/HDMI, TV W/HDMI, But Non-HDMI Receiver?

Xbox 360 w/HDMI, TV w/HDMI, but non-HDMI receiver? - best hdmi stereo receiver 2009

With a view to a buy Xbox360 w / HDMI. I have a plasma TV with HDMI, but my Sony stereo head unit is quite old. No HDMI on that point. Will I be able, 360 audio through an HDMI port is not running (such as digital optical or coaxial), while with HDMI connected to TV? Or am I obliged to listen to it through my speakers on the TV or buy a converter or HDMI receiver?