What is "GREY MARKET" again?
Grey market refers to a camera coming directly from Canon via the dealer without any Canon USA warranty. Might be a non authorized dealer. Many authorized dealers do offer both USA and grey market versions. Typically these dealers will provide their own 1 year warranty. So if something goes wrong with the camera within that first year, you need to contact your dealer (i.e. BH or Adorama) and they handle the repair. With a USA version, you get 1 year warranty from Canon USA and can get the thing services by Canon USA and CPS.
Thats my understanding. Please others chime in, if I'm not on the mark.