Best low light body you can get in that price range is a D90. Look for a refurbished unit. The D300 would be better due to more focus points, bigger viewfinder and FPS, but is probably too expensive even used or refurbished. A D200 does not have the high ISO capabilities and is not as good a choice as the D90.
Next is the lens. Indoor basketball has some pretty low light, so you are going to need fast glass. You are also going to need some reach and the ability to change the focal range, so that means a telephoto zoom to me. Here are some suggestions:
1. Nikon 80-200 f/2.8 two ring model. or the afs model.
2. Sigma or Tamron 70-200 f/2.8. The Tamron is reputed to be sharper. Both have reports of struggling AF in low light.
3. Sigma 50-150 HSM II - This lens will be a little short at 150mm for the far end of the court. but it is fast focusing and is pretty sharp. You may have to stop down at 150mm to f/4 to get better sharpness.
Then you will want a nice flash unit like the SB600 and a good set of rechargeable NiMH batteries. Shoot rear curtain.
You may be doing more burst shooting to catch the action, so invest in the SanDisk Extreme III (30MB/sec) cards. These cards almost double the number of shots you can cram into a 30 second shooting marathon.
A monopod may help to steady the camera and help in the low light conditions. You are still going to need a high shutterspeed to stop action, but the monopod helps you keep steady.
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Catallaxy