actually, i was in the same boat as you. I managed to get the xbox media center working. I did further research and it is open source created by people on their free time.
I was basically looking for a linux software which will play xacti hd1000 videos and this one plays them just fine. the xacti hd1000 files are 1920x1080 i or p and it is just awsome to see it running on my desktop. I am planning on buying a xacti hd1010 or a hd1000 this thing plays dvd's too.
here is the tutorial
go to system->administration->software sources
click on third party software and add these two
close and reload
open terminal and enter this
sudo apt-get update
and now to install
sudo apt-get install xbmc
you can launch it in applications->sounds & Video xbmc
or in terminal type xmbc
There are tons of skins, and tons of plugins and I mean tons. you just need to look very hard.