The 105 mm VR macro is an AF-S lens. I have one, and it focuses quite fast (for a macro). It's great. It's also more than the OP's budget, unfortunately. However, for macro, he's not losing much. I use the AF on my macro, and then manually adjust the focus from there. It's very fast.
Too bad the viewfinder on my D50 was too dark and too small. I remember the D40's viewfinder being much better.
Even with good vision, manual focus wasn't a particularly easy task on my D50. I was going to replace it in like 6 months, but now that I messed it up, I guess now's the perfect time to replace it.