It all depends on how serious you are about your macro photography. A true macro lens will normally trump a zoom w/macro capability on image quality. But, if you only shoot macros occasionally, then maybe the zoom would be a better choice.

I have a Nikon 60mm f/2.8 macro (or micro as Nikon calls them). I absolutely love this lens. It is incredibly sharp and provides results yielding excellent color and contrast. The 105mm is more commonly recommend, but also costs about $200 more.
I've obtained excellent results from both my D70s and N80 with the 60mm.

Good luck!

I second the advice of using a proprietary macro lens over a one lens do it all OK but not any one thing excellently.

I find that a manufacturer's macro lenses to be about the sharpest of the lenses in their line. I own four of Nikon's and would never sell them.

If you're using one of the $1000 bodies, you need to use an autofocus (60mm) lens, but if you're using one of the higher end bodies, you can use the older, but excellent, manual focus macro lenses. You don't need autofocus for macro...

I agree. I use a dedicated macro (60mm) with a D70s and find the results to be far superior over a "do it all" lens. I've tried macro with my 70-200mm just to see the comparison and it just isn't there.