I'm having an issue with my RP where my keyboard is not detected. I have raspbmc installed on my SD card. Pressing any keyboard keys has absolutely no effect.
I first thought it was a power problem because this seems to be an issue that many people have when their keyboard is not working properly. I have a 5V/1.2A micro USB power supply that I have ordered from RS electronics together with the RP. However, not even the numlock/capslock LEDs are lighting up on my keyboard. Note that the keyboard has no backlighting or an integrated USB hub and that the keyboard works fine on my PC. Furthermore, if I plug in my phone to the RP via a micro USB cabel, the phone indicates that it is being charged, i.e. the USB ports actually provide power.
Edit: Forgot to mention. I'm using a Logitech K120 keyboard which is listed in the list of verified peripherials, see http://elinux.org/RPi_VerifiedPeripherals