[Dave]

1) Landscape - Sigma 10-20mm
2) Portrait - Nikon 50mm f/1.8
3) Children - Nikon 17-55mm f/2.8
4) Macro - Never done it but would suggest Sigma 105mm Macro
5) Architecture - Sigma 10-20mm
6) Water scene - Nikon 17-55mm f/2.8
7) Sports + Action - No longer have long enough lens, but from old - Sigma 70-200mm f/2.8
8) Animals + birds - No longer have long enough lens, but from old - Sigma 70-200mm f/2.8
9) Low light or night photography - Nikon 17-55mm f/2.8
10) All purpose photography - Nikon 17-55mm f/2.8