Got it a few weeks ago, put Debian onto a Transcend card, got it up and running happily using a wireless keyboard/trackpad (mentioned in the Wiki). Was able to connect via RJ45 port too. Also put OpenElec on another SD card and got up and running to a point with that, though it didn't seem to want to know about USB. Put a pre-RC RaspBMC onto another SD card and had similar mixed success. Put it all on one side for a little while. Came back to it today. On booting, got many "New USB device" messages, even when there was nothing in the USB ports, and kernel panic.
PSU is the same as I had running successfully.
Used RaspBMC RC3 and Debian6 19-04-12 (tried a freshly burnt one). Results are the same. ISTM like it could be an issue with the USB port driver. Does anyone have any ideas or has anyone experienced the same thing?