First, for macrophotography, hand held, a stabilized platform is a good idea, especially since you don't seem to be doing any 1:1 macro shooting. Canon only has one optically stabilized macro lens, and Nikon only has two. Since Pentax and Sony use sensor shift image stabilization, all lenses are stabilized, so the OEM macro lenses plus all the third party macro lenses would be stabilized, including all the excellent lenses available on the used market. Also, a good macro lens could do double duty as a portrait lens.
Second, the Nikon D40/D60/D3000/D5000 are not very good at sports/action. Canon would be best, and the Nikon D90 would do an excellent job , but Pentax and Sony dSLRs could do reasonably well.
- The lens is the thing.
- 'Full Frame' is the new 'Medium Format'.
- "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.