If cost is not a factor...
Nikkor 105mm f/2.8G ED-IF AF-S VR. One of the Nikon guys here on the board has one, I think its Gdad. Awesome lens. Goes for around $850.
But you said price wasn't a factor. If focal length isn't a factor either, then the Nikkor 105mm f/2.8 is the way to go.
I use the Canon 100mm 2.8 macro lens and absolutely love it!!!! Heres a link to my gallery using this lens http://www.pbase.com/catson/canon_100mm_f28_macro