I like some of the pictures, but I think you might want to watch your verticals and horizons some - I'm personally not a fan of wierd angles in most pictures, such as the squirrel or some of the food shots (though I like the squirrel picture otherwise).
I was going to suggest considering the Sigma 105mm Macro 2.8 that I got for about half that price, but it looks like it was just replaced with a much more expensive model
However, Tamron makes a couple of 90mm, 100mm macro lenses in Nikon format that are under $500 that might be worth considering.