If you travel to Canada and want cellular service for more than emergency use, then plan on purchasing a local SIM card and perhaps using Telestial or another International virtual GSM network provider for inbound service.
Note that the last version of the Verizon Galaxy Nexus (i-525) does not have a GSM radio and thus will not work for international service except in about 35 CDMA compatible countries.
Japanese mobile-phone makers were so busy competing with one another at home, they took their eyes off the international arena, allowing relative unknowns Nokia and Ericsson which correctly anticipated the dominance of GSM to grab the largest slices of the pie.