Wow, your post sounds like it should have been in the thread called "On the way to the home theater..." or whatever it is called. Tough man. I feel for you. With all the standards, connectors and wiring needs, setting up a home theater is no longer just about truning the TV on and sitting back. If you go the receiver/ seperates route, the road can be bumpy indeed. Not to mention the number of people out there waiting to profit from the inexperience of people like yourself wanting to make the switch from a HTIB or BOSE to something more satisfying.
I hate to break this to you but, there is no receiver on the market today that will provide a single wire solution. There is conflict between HDMI version on the receivers and the TV STB. Not even the top of the line in Yamaha, Denon, Pioneer or any other manufacturer you can name. The only way to implement a single wire solution (only one wire goes to the TV from the component rack) without purchasing a new receiver (which will not work) is to get a HDMI switcher.
Route the video via HDMI out from your Xbox, DVD player, STB through the switcher to the TV. Route all audio through the receiver. Set up the HDMI switcher to give video for the corresponding source and you have your dream setup.
More replies should be pouring in soon. Be warned, a lot of folks will suggest you return the Bose speakers. Their suggestions are justified. For the cost of the Acoustimass 16 - 6.1 setup, you can get much better performing 6.1 speakers. But I am sure at this point you just want to get your existing setup working... so I will refrain from making suggestions on this front.