Sweet! Our new XBMC box is online. It automatically downloads our TV shows from Usenet (yeah, it's still around, apparently) sort of like a DVR without needing a cable hookup. It even speaks UPNP with our Mythtv box so we can use the XBMC box it to watch stuff we DVR'd with the Mythtv box. Might eventually merge the two so I'm not running two PC's in the living room, but I'm afraid to touch the myth box after 4 years of off-and-on hackery.
The nice thing about XBMC over mythtv is that it downloads videos in HD, our old mythbox only has analog tuners. The XBMC box was built with XBMC Live and hooks to the TV via an DVI->HDMI adapter. I didn't even have to fiddle with X-window timings (remember those days?). I am using a HP MCE infrared remote sensor which works with the Logitech Harmony so we still only need One Remote to bring them all and in the living room to bind them.
The only hiccup I had with the build was getting the HP MCE USB sensor working with Linux and LIRC, the infrared driver. The USB ID of the device was not in the kernel module as supplied by XBMC Live (Ubuntu), however after a few hours work work, thinking I'd have to relearn how to compile a modern linux kernel, I found that it's possible to recompile a module based on the current kernel, so I just had to recompile the module (with the new USB ID's in it) and not the whole kernel itself (phew!)
% cd /usr/src/linux/ubuntu/lirc/lirc_mceusb/
% make -C /usr/src/linux-headers-`uname -r` M=`pwd` modules
% make -C /usr/src/linux-headers-`uname -r` M=`pwd` modules_install
% depmod -a
% modprobe lirc_mceusb