Digital Slr Camera Lenses Explained

I am looking to buy a digital camera …?

I am looking to buy a digital SLR camera. I do not know much about these at all … but I'm looking for a camera that will take pictures of the big picture. I just learned that the "depth of field" is what makes a good shot picture … but could someone explain this concept to me? Does the depth of field ranges from camera to camera, depending on how good … or not your lens to determine the depth of field? If it is dependent on the lens, what kind would you suggest buying? Thank you!

I suggest the Nikon D90 http://www.nikonusa.com/Find-Your-Nikon/Product/Digital-SLR/25446/D90.html () For between $ 899 – $ 999

Canon EOS DIGITAL Rebel XSi 18-55MMB Digital SLR Camera