Summary: It is broken, the breakage is known, and it is being worked on.
It's a shame apt-get doesn't spit out something more helpful than "need this but I ain't gonna install it :-P", because, as a Debian newbie, I always assume I've upset it somehow :-( Until the dependency problem is fixed, is there any way to "force" an installation? I'm guessing KDE would mostly-work without ksysguard? Or am I just being impatient? Cheers, Jon