Why did you choose a Canon camera? Why did you choose a Nikon camera?
I'm curious to know why you chose the cameras that you use. My story starts with me buying a Canon A1 in the 80's and later a Professional Canon F1 camera (still have this one). I chose Canon at that time because I was impressed with the quality and clarity of the 35mm images that it produced. It was also the first SLR that I was introduced to by my personal friends and the photographers that I hung around with. I really enjoyed that camera and bought quite a few lenses and accessories for it.
A few years later came "auto-focus". I'm told by Canon that if I upgrade to one of their "new" (at that time) auto-focus camera's, my "manual" lens would not work (become obsolete), requiring me to not only buy a new camera, but a complete new set of lenses. That rubbed me the wrong way. So after looking at my options decided to jump ship and go with a new "Nikon" auto-focus system.
One of the reasons that I use Nikon is that all Nikon 35mm SLR and DSLR cameras past and present use the same lens mount, allowing you to continue to use your manual lenses on your auto-focus cameras, sans the auto-focus function. That was enough to convince me that my lens collection would not go out of style.
So, why did you choose the camera that you are using???