Welcome.
If we can help out, we will.
On first glance, the 8800 will need to have newer drivers installed. These are detailed on the wiki page:
http://wiki.linuxmce.org/index.php/Display_DriversThe amplifier can be controlled via IR at the very least. So you will need an I/R transciever. The ones that work best with our system are:
* USB UIRT (this was shown in the demo.)
* GC-100 (transmit only)
* IRTrans
* Tira
I use a USB UIRT in my system, with a Xantech 286 double emitter on mine to control my TV and cable box.
If the Ethernet recorder box exposes itself over UPnP, LinuxMCE will scan all its publically available media.
The XBox 360 isn't supported yet. But some of the developers do have the boxes, so I think we'll see support for it on the UPnP level. The drive is supported, however.
I recommend that you look at the FAQ on the wiki to start, and there is a chat function to get help here too.
Good luck!
-Thom