I have several Nikon bodies but typically only use one. I selected Nikon because I always considered them the top of the line. This is only a perception on my part, but I always liked their optics best and the camera is only as good as it's lens (and the human behind the camera).  The other reason I like Nikon is because of the incredible market in used equipment.  Buying and selling used Nikon equipment is very easy. Sometimes "popular" is more important than "best". Canon also falls into the "popular" realm and many people prefer Canon over Nikon. Each has it's advantages (Canon: AutoFocus, Nikon: Metering), but that keeps changing as new technology evolves.

I started out with a Nikon FM, went to a 6006 (didn't like that very much) then an N70 (didn't like that either), upgraded to an F4s (loved that) and finally, in April of 2000 upgraded to an F5.  The FM, 6006 and N70 lacked features I use a lot -- mirror lockup and depth-of-field preview.  The N70 would have been OK, but I found mirror lockup to be an essential part of taking sharp pictures. With the combination of a long lens (300mm and up) and slow film, the mirror vibration takes it's toll on sharpness with slow shutter speeds.  Mirror lockup has mostly alleviated that problem for me.

The F5 is what I considered to be the ideal camera - exceptional metering fast autofocus (although I don't use that very much) and lighter than the F4s.  It has lots of electronics (both a positive and negative point), depth-of-field preview, mirror lockup, double-exposure, electronic cable release capabilities (but no mechanical cable release!), a very bright and exceptionally sharp 100% coverage viewfinder, and takes standard "AA" batteries (8 of them). It's autofocus is rated very highly, but I don't often use autofocus (something I find superfluous when shooting on a tripod!).

Sometime in 2003/4 I purchased a Nikon D100 6 megapixel digital camera.  I obtained some amazing shots with it and was able to get beautiful 16x20 prints from it.

I just recently sold my F5 - a task that I found very difficult to do.  But, I'm hooked on digital now.  In March, 2005 I purchased a Nikon D2X and am finding that I am getting FAR better images with that than with the best camera/film combination (F5 and Fuji Velvia) I ever used. The level of detail, color, tonal range, etc., etc., etc. is truly amazing.  I could NEVER go back to film now - something I didn't think I'd be saying for another 5 or 10 years!

(see my discourse on fim vs digital here).