Hi there

I am a complete novice at photography, currently own a 35mm compact camera :-), but am now thinking of buying myself a digital camera for personal use. Basically, I want a camera that can take pictures of images at a distance (wildlife, scenery etc), as well as close up , that will be easy to use, but will also have enough "features" to allow me to grow with it and become a decent "serious amateur photographer".
With everything I've read so far on different web sites, I am leaning towards the Nikon D70, but before I commit I'ld just like to clarify something which I'm not sure about - besides for the features, clarity etc advantages that a DSLR has over a all-in-one digital camera - what I'ld like to know is what is the difference between their lenses
eg: The Nikon COOLPIX 8700 has a focul length of 35-280mm, does this mean that I would be able to take more or less the same pictures at the same distances with the COOLPIX that I would be able to with a 28-70 and a 70-280mm lens on the D70. Or would their be a substantial difference.
If the focal length on the COOLPIX is equivalent to the D70 with the above 2 lenses, then I assume it would be more practical to have the COOLPIX so that you don't have to carry around all the extra equipment etc.
Also , on the topic of lenses - how far away (feet/meters) in real terms would you be able to take a picture of a person with a 280/300mm lens so that it appeared that it was a closeup?

Thanks in advance