Do the HDMI output 360s have the same output that my non hdmi unit have plus the HDMI port? I'm assuming they do. If they do, and you plug in both an HDMI out and the Component out, how do you choose which one sends the signal? The the system have the ability to choose via the setup screens or does it choose one by default over the other when it is detectected? The reason I ask is I have a nice Sharp DLP projector that takes VGA but also takes 1080P DVI-D input. I have a 50' HDMI-DVI-D cable that I'm using with my PS3 and would like to get a switcher and be able to plug everything in without having to constaly unplug stuff.

In other words, I may wait until there is a sweet ass deal on an arcade bundle with HDMI and grab one. I'll sell my pro without the hard drive on craigs list, ebay, etc.

To answer your first part about the outputs the answer is yet. It has the standard "component" plug plus the HDMI plug. You can plug both in at the same time as long as the HDMI cable isn't too thick. I had a Philips brand HDMI cable that wouldn't allow me to plug in both but the MS branded one and a $8 monoprice.com cable both worked fine.

As far as your second part I'm not sure. I know it will output audio from both ports at the same time. I have the HDMI running to my TV and use the other output port to supply a separate audio signal to my Turtle Beach headset.

I guess I should have made my objective more clear:

I want to plug in both the standard composite cables into my receiver for playing on my television AND plug the HDMI plug into an HDMI selector. When I want to run my projector, I want to be able to "tell" the 360 to output video over the HDMI via the blades and audio to remain through the optic cable. This is how my PS3 is set up and I switch back and forth without having to jigger cables all over the place. If I can, then I'll sell my non-hdmi pro core on craigs list or ebay and get a newer arcade with an hdmi port.

Thanks.

Pretty sure you can from the display menu.

In a way that's exactly what I'm doing.  I guess I should have been more clear too :)

The only difference is that I'm outputting the video to my HDTV with HDMI then a seperate audio signal via the component cables to a headset receiver instead of a Home Theater one.  I don't know about setting up anything in the menu because I just left the video output cables unplugged.