I have sold cameras for some years now and it is my opinion that Canons aren't the best are far as usability is concerned. I'm not saying they are terrible mind you, but I believe Nikons to be easier to the newbie. Both brands make excellent cameras based on technical merit - great picture quality, well built products, great selection of lenses. I am not a pro, I only own a D40 - because really, it does all I need it do
. And I'm a student who can't afford to spend thousands upon thousands on higher end gear
If you were to ask me right now which brand to get as a newbie photographer, I would say opt for the Nikon. But then I would say, don't be a fool - go visit a camera store first and play with these cameras in your hands first and foremost. You could bring an SD card if you'd like to compare photos between the cameras but really, at this level, there isn't much to complain about.
With a D40, an entry system would be the camera body, an 18-55mm wide zoom, the 55-200 VR for telephoto, and the 35mm AF-S.
With a Rebel, an entry system would be the body, the 18-55 wide zoom, the 55-250 IS for telephoto, and the 50mm prime.
Lastly, for the Nikons, if you were to find/buy older lenses from yesteryear, you will need a D70/80/90/200/300 and so on; the D40/60/3000/5000 cannot autofocus these older lenses, you will have to manual focus. If you're not going to be buying older lenses, then this is moot point.