Ok, i've decided on the length of lens i want, but now the choices...
I have a D90, 18-105, 50mm 1.8, 8mm and would like something longer.
I've looked at
Sigma 70-300mm f/4-5.6 APO DG MACRO
Tamron AF 70-300mm f/4-5.6 Di LD Macro
NIKON AF 70-300mm f/4-5.6 G Zoom Lens F4-5.6
Are any of these worthy? I'm trying to stay under $500 but if i am willing to save longer if these lenses wont cut it.