I have come across some very good news to those who, like me, own a Logitech Audio Hub USB speaker system. Until now it did not work properly on Linux systems, there was always a constant clicking in the sound. I have been dragging it back out and trying it again from time to time, as new Linux releases come out... and I am pleased to report that it works beautifully with three of the current test distributions I just tried - Ubuntu 9.10, openSuSE 11.2 and Fedora 12! Hooray!
What all three of these releases have in common is Linux kernel 2.6.31, so I am assuming there has been some kind of fix in the kernel that took care of this problem. I just tested it again with Fedora 11, which has Linux kernel 2.6.29, and it still has the noise on that, so if it is a kernel fix, it must have been in 2.6.30 or 2.6.31. I don't have anything around here right now that is running 2.6.30, so I can't narrow it down any further.