I asked a friend (she is a professional photographer) the same question about a year ago and here’s what she said:
Nikon has 3 lines essentially.
Consumer – tends to have sillier bells and whistles (i am biased, but in camera slide show generation is not a priority for me) price range around $500-800 for a body with a couple “kit lenses” more on that in a bit
Prosumer – tends to be very high end, less silly whistles, more functional features price range around $1000-1800
Professional – extremely droolingly high end. cost prohibitive. (seriously, $5000 for a body…. if they get sold in kits, i will piss myself laughing… more on that next)
you used to be able to tell the lines apart by the number of digits in the model name… 2 (d70, d80, d90) = consumer 3 (d100, d200, d300) = prosumer 1 and sometiems an extra letter = pro (d2, d3x)
but they’ve been blurring that line more and more. d5000? consumer d7000? prosumer… yipes.
so price will determine
kit lenses – awesome and evil.
They will do the trick at first, but if you want to shoot low light, indoor ambient light, no flash photos – you’ll get angry and frustrated. they typically have a widest aperture in the 4 – 6 range. this is called “slow” it will be hard to achieve a decent shutter speed in a lot of situations with those lenses. also – depth of field will never be very shallow (fuzzy areas vs crisp)
but kit lenses can help get you into a camera sooner, so awesome. my advice: buy a camera body and pick your lenses. if that’s financially tough, buy a camera with one decent kit lens, but don’t put a lot of money into a kit package.
hope that’s a good start!
oh yeah, and canon has a REALLY hard time focusing in low light – currently that’s the big difference. some photogs carry a flashlight just to make focusing in low light quicker/easier…
Now, based on her input, we actually ended up with a Pentax (I would have to go get it to find the model #) and it’s wonderful. It is actually our second Pentax; the first, we had for less than a month when we left it behind in a hotel lobby and never saw it again. That camera was the higher-end one and cost about $1500; when we replaced it, we opted for the more mid-scale model, at about $900, not wanting to lose another $1500 camera. It came with a kit lens and we’ve since added 2 more lenses. Can’t be happier with the quality of the photos and the straightforward controls; the $1500 model also took gorgeous photos but was a bit too much camera for us, too many buttons (the one we have now also has a ton of buttons and options but still about 30% less than its higher-end brother).
I hope this helps!