Camera loyalty tends to get vicious because there is so little difference in actual quality that the decision really does come down to personal preference. And most people with a brain in their heads know that Nikon is superior to all others.
I wouldn't say that I'm seriously loyal to many brands, but there are definitely certain brands I prefer over others.
-Ford for vehicles (although right now I own a Dodge and a Chevy)
-Dell for computers (yes, I know computer snobs hate them but I've owned 5 of them and never had an issue)
-K2 Skis, Marker Bindings, and Salomon boots
-Foremost chocolate milk
-Panasonic electronics (although almost everything in my house right now is Sony)
-Diet Dr. Pepper for drink of choice