I have LMCE setup and my sky+ box connected in a manner
I use a pvr150 and input via the svid input for best picture quality.
I am currently using mythtv as vdr is not quite yet fully working on the mds as far as I can make out.
I have ordered a USBUIRT but it has not arrived so I have not set up any automated channel changing and instead just use the normal sky remote to change channels. when it does arrive this is the next thing for me to look at.
for information on this I was pointed to http://www.mythtv.org/wiki/index.php/UK_Television
by other forum members
I have not had any experience with any ATI video capture cards as when I first came to the project, nvidia seemed the best way to get UI2 and alpha blending and a pvr X50 was the way to go to get a live cable/sat box input.
I think the first thing to probably try and do is establish if the capture card works just within kubuntu, and then once its working there it should just be a matter of setting it up within LMCE.