Media center stuff is pretty well figured out these days. Between VLC, the various Linux programs for controlling satellite and.cable, and the resources that Valve has, I think it's reasonable to expect quality that meets or exceeds Windows 7. If this does well, you can also expect native apps for Netflix and whatnot.
If successful, this will go a long ways towards making Linux the future of gaming. I think it will be successful, so I am pretty happy.