It is a question that I had to answer for myself, and sure many others
need an answer, and the answer would need some effort and especially
from those who did not try any and need an answer to decide.
Well, Nikon and Canon are very close really, any of us would never
regret buying neither if it is about a camera and set of lenses,
photoshop after that would complete the work.
For a simple user who is not looking into details, Canon would
look like a shining star because of their image sensors which reached a
high value few years before Nikon and they produced the full frame
sensors and used them in their cameras around 5 years before Nikon. This
is because Canon used to use image sensor technology called CMOS while
Nikon have been using CCD, and when Nikon used CMOS in there recent
models they could produce full frame sensors with high resolutions upto
24.5 Mp (Highest Canon is 21.1 M).
Comparison between CMOS and CCD can be found here: http://www.dalsa.com/corp/markets/CCD_vs_CMOS.aspx
Canons are cheaper when it comes to their high line models (professional
models with Full frame or 1 focal length multiplier) and can reach half
the price of the Nikon in that range while Nikon are cheaper when it
comes to their medium and advanced amatures DSLR(with 1.6 focal length
multiplier).
Canon lens mount is a problem because you cant use old lenses on new
bodies, and some bodies can only accept EF mount lenses, while you can
always use old nikon lenses on almost any nikon digital body. So, if you have old Nikon set of lenses for film cameras and external light meter You already know the suitable answer for you. And
above, Nikon has some range of bodies that have the light meter build
on the body, so you will not need an external light meter (as in Nikon
D200).
Canon has a larger market share in Egypt as far as I saw and know, and
Canon is putting some effort to start their CPS (canon professional
service) in Cairo.
Canon resellers (including the agent) are selling the Canons for
competetive price while Nikon agent in Egypt is really expensive.
Canon accessories can be found easily (dont be sofisticated, just simple
accessories as batteries, battery grips, some lenses and some
compatible lenses), while special accessories have to be ordered from
somewhere abroad.
If you have a serious problem you will not find a way than sending the
camera to UAE to be fixed (cheapest and closest destination to Egypt).
As a last point, and this was the final point to choose a Canon for
myself, I had most of my friends using Canon, and I can always have a
supply of accessories if I need what I dont have. So, what about you?
You can always find full specifications of cameras if you check: www.dpreview.com