Do you really think that an unlocked phone will end up in Canadian Best Buy stores? Besides, 3G on the phone will only work under Wind. So far as I understand it, it breaks down as such:

    Canada          U.S.
    ------          --------
    Wind            T-Mobile
    Rogers,Bell     AT&T
  

All GSM phones will work for phone calls and Edge for internet, but 3G tech is outside of GSM. Due to controls over frequencies by the government, each of these networks has carved out their own band to use, which puts different hardware requirements on phone manufacturers (this is in addition to CDMA vs GSM).