anw out of curiosity.. Everytime i saw a sports events like soccer or Olympics.. i realize that most camera's are using canon. is something go to do with sponsorship or personal
my guess is that when canon came up with the 1D II, its superior fps (8.5fps at 8.2MP) made it unbeatable when it comes to shooting sports (nikon D2x came out later than that IIRC), so most news agencies switched over to the canon system..over the years, it'd be cheaper to stick to the same system as old lenses can still be used on newer bodies.
though i believe that there are still individuals in AP/AFP/etc that still stick to nikon even though their company uses canon
To expand on +evenstar's comment, I think Canon also had better noise control at higher iso a few years ago. Higher fps and better noise control are ideal tools for sporting events. Also the extensive line-up of lenses by Canon helped.
Nikon's current line up has definitely shaken things up though. But switching over when you are heavily invested in lenses does take some second thoughts.
Dunno if i should be saying this here.... But i heard that SPH have since switched to nikon shortly after the D3 was launched.... (that's abt a yr back or so)
To make a statement that "you need a FF camera to fully maximize a large aperture lens" is misleading. There is more to shooting sports than just having a larger sensor camera.