Troubleshooting HDMI connection between MBP and Sony Bravia TV
This problem could also be caused by a missing or improper HDCP signal coming from the MiniDisplayport-to-HDMI adapter. 

I experienced the same issue with my MacbookPro (late 2008) and a Bravia TV. I tried one cable with a MiniDisplayport connector on one end and HDMI plug at the other. This worked fine between my MBP and a computer monitor or a beamer, but would not transmit any signal to a Sony Bravia TV. An adapter (of the cheaper kind) displayed the same behavior. The used HDMI cable was fine (tested between PS3 and the TV). Again, adapter and cable produced a proper signal on non-Bravia displays. A Dr. Bott MiniDisplayport-to-HDMI adapter finally solved the matter for me.