This may be related, but I'm having serious trouble with USB keyboards on my RasPi (currently running Arch Linux ARM).
I've mainly been using a USB wireless keyboard/trackball (an A.N. Other-brand one from Maplin - the dongle is plugged into a Belkin powered USB hub), and most of the time I get the dreaded repeating keypresses problem, which the FAQ states is caused by inadequate power from the USB supply. (I'm using one of those Master Plug USB chargers that Sainsbury's were selling off a couple of months back.)
Worse: when I plug in a wired USB keyboard (admittedly, a dirt-cheap one from a discount store), the RasPi freaks out and sprays hex codes all over the screen, before finishing with a "kernel panic" error message.
Basically, until I can solve the "repeating keypresses" problem (or bypass it - would remote access via SSH be affected?), my RasPi is unusable. Can anyone recommend a USB supply which is known to deliver the required power, consistently and over time?