Hmmm, I started to give the same answer as already given in this threadhttp://forums.dpreview.com/...forums/read.asp?forum=1030&message=25390359.
So one open point remains:.
How many $ are you willing to spend now and in the following time for cam(s) and lenses? Fast tele lenses are expensive (indoor sport)..
I have a D200 and recommend it - though there is no real kit lens. But the D80 will have similar image quality but not the build (or weight). I have a 17-55mm f/2.8 on mine most of the time but that is expensive. Quite a good all purpose lens is the 18-135mm..
A couple of inexpensive lenses I might recommend (which wouldn't autofocus on the D40x) are the 50mm f/1.8 or 85mm f/1.8 - these would be good for kids, portraits, indoors generally, and indoor sports..
Indoor sports is where you really need f/2 minimum and preferably f/1.8 or f/1.4 widest aperture - the cheap zooms like the 18-55mm won't hack it. But it depends on how close you can get to the action whether 85mm is long enough..
I guess I am willing to spend a reasonable amount but probably not over the top.. had dreamed of going professional but I can't see that happening now..
I started off with a minolta and sigma lenses, and they were pretty good. I loved my nikon and initially had tamron lenses with that. If it wasn't for the convenience of digital I would still use it..
So I guess I would prefer to spend more now, and get the right lenses that will work for me : an everyday kind of lens and also one which would be suitable for the sports stuff. If this needs to be two lenses, then it needs to be two lenses..
I would skip the D40(x) because of it's limiting options, especially according suitable lenses (only AF-S or Sigma HSM lenses will autofocus)..
As an everyday body / lens combination look at the D80 with the 18-70mm f3.5-4.5 or 18-135mm f3.5-5.6. Both are good lenses already from an amateur point of view. The first one with a slight better image quality but less reach than the second one..
If these lenses aren't fast enough for your intended use, have a look at the Tamron 17-50mm f2.8 (or the pro grade Nikkor 17-55mm f2.8, but it is 3x expensive)..
For indoor sports you will need an f2.8 tele lens at least. To avoid shaking blur at the long end (i.e. 200mm longest hand holdable exposure is 1/300 sec) an image stabilzer (Nikon: VR - vibration reduction) is usefull, alternatively the use of a monopod could help. To avoid motion blur of you (fast) moving subjects, 1/250 or 1/500 will be needed too. Here I see the following alternatives:.
Nikkor 70-200mm f2.8 VR (pro grade, expensive, but very good glas), Nikkor 80-200mm f2.8 (if you can find an used one in mint condition, because it is out of production) or Sigma 50-150mm f2.8 (affordable, no VR, but 150mm means hand holdable from 1/225 on)..
I would complete this selection with one fast prime at least as there are Nikkors 50mm or 85mm with f1.4 or f1.8 for portrait or dark indoor use. To take pic's at home the Sigma 30mm f1.4 could be usefull too..
.... and if you are willing to go deeper into photographic details(*) and some money is left, exchange the D80 with the D200 (my cam of my last post..
I preferred it against the D80, also because of it's better fitting and feeling in my hands!.
(*) D200 has no automatic programs like portrait, sports, night, landscape, .... You have to adjust it by yourself. Also postprocessing your pic's will be more apparently, because the D200 tends to underexpose to save the high lighted parts of pic's. But this can be compensated also by in-cam options, of which the D200 has more than the D80 (be warned: you can get lost .... ...