I use canon SLR's Film and Digital for more than 10 years.... BUT in the last one an half years Nikon is wiping the floor with Canon in terms of semipro and pro cameras... In terms of resolution, IQ, features, diversity AND MOST IMPORTANT PRICE. I know Canon L series is over Nikon top lens in terms of quality and diversity.
After 10 years of using Canon gear and last 2 years for professional photography i really considering switching to Nikon if Canon will not respond ( and i don't mean especially to Nikon D600 ) to Nikon. By this i mean by introducing a affordable entry lvl FF, a significant drop in price regarding 5D3 and an entry lvl sports/wildlife crop sensor ( called 7DMk2) with improved IQ.
Regarding the new Nikon D600..... two words: WELL DONE Nikon , no comment.