It starts up with the correct input due to CEC. Although, Sony and Samsung's version of CEC - Anynet+ and BraviaLink+ - aren't officially compatible, is seems that powering up uses the same code so that actually works in your favor.
In most cases, the television may revert back to the Always On connection - the co-ax tuner, even though the may or may not be anything plugged into it. That's the only priority I know if when a HDMI port is disconnected.
I just purchased a new LN40C630 which is amazing! I have a question about setting HDMI priority. I have both a Tivo Premiere and a Sony Blu Ray player. Each goes into a separate HDMI port on the Samsung. When I turn on the Blu Ray the Samsung automatically switches to the correct HDMI port and I can watch a movie. When I turn the Blu Ray player off, it doesn't return to the Tivo, it goes to an empty HDMI port and then an input that has no input at all.
How can I get it to return back to the Tivo's HDMI port after I watch BluRay? Are the ports arranged by priority?
For the record, I have another set with a first generation Tivo HD and a Samsung DLP with only one HDMI port. I bought an Oppo 3-port HDMI switcher and what I described above works perfectly. Port 3 has the lowest priority, which is where the Tivo is plugged in. The BluRay player is in port 1. When the BluRay is turned off, it returns automatically to the Tivo. That's exactly what I'm trying to achieve with my new LN40C630.
In advance, thanks for any input you can contribute on how to do this.