What is a High End Camera?

I'm looking at getting a Nikon. I was told by a Nikon user to get a higher end camera and pay a little more because later down the road, additional lenses are cheaper. So pay more for the camera now and pay less later. If that is true, then what is considered a Higher end camera? What are some of your suggestions? What Nikon SLR is your fav? Thanks!

Added (1). Also, what is a really big zoom lens. I mean, I want to use a tripod and get pics of a full moon. How does the zoom #'s work? When I get my Nikon, what is a good zoom lens?

Added (2). Thanks for all the great answers! I have been using an SLR for quite some time and know how to use them, but when it comes to my own camera, I'm a little clueless, because I don't want to throw a few hundred dollars down the drain. I'm sure I'm going to be happy with what ever camera I get, I just don't want to be spending tons of money down the road with it.

D3100 is the best if you are new to dslrs
it has a guide mode and is the newest one they have i believe that would be a $6-700 range camera if you want better, there's the d7000 and d300 if you're really serious, there's the d3x
i would get the d3100 because of the price and also it has continuous auto focus during video (24fps at 1080p) the lens is more important than the camera from what i've heard.
the source below is the list of Nikon d-slrs

Actually I'd advise differently from your friend. Lenses are the most important part of the image quality - the camera bodies are pretty much just where the features are. Bodies change & new ones come out every few years. Good lenses never age though - especially with Nikon, where new bodies can take all old Nikon glass (most of which is high quality)

I'd recommend getting an entry level body (like the D3100) - this is an excellent spec body. Get some good glass as well. If you then progress with your photography you can upgrade the body & your lens collection will be fine for the new body.

If you must get a higher end camera, then I'd suggest starting with a D90 - it does have an autofocus motor (which the entry level cameras don't) but still has auto modes, useful for a beginner to DSLR's.

A high-end camera has more control range and easier control access. You will notice that higher-end dSLRs have two wheels, one in front and one at the back.

To get a picture of the moon, you don't necessarily need a big zoom lens. What you need is a lens with more focal length. If you can afford a 1000mm lens then you could get closeup shots of the moon.