are you shooting DX or full-frame?
true that the 105 would give you more space between lens & subject, but I actually prefer to do most of my macro work handheld (!) with aid of (a few) flashes, so in DX format the 105 often feels a bit too long. For whatever reason, I've tried to get along with the 105 numerous times, but I keep coming back to the 60mm as my favourite for shooting DX format. Especially on flower photos, this lens really shines.
if you're looking for something with the 90mm focal lenght on an FX body (i.e. same as the 60mm on DX body), then the Tamron 90mm is supposed to be good, though i've not tried one extensively myself.
now (and i'm getting ready to duck in case the purists catch me), if you manage to find the excellent 70-180mm nikon Macro Zoom (and can afford it), then I wouldn't hesitate a a moment to jump on it. it's particularly great for shots of 'shy' bugs, where moving back & forward to re-compose may scare them off.
finally, re: VR feature on the new 105. that may not be much use for Macro work, but if you choose to double the lens up as a portrait lens, then VR is may be helpful. But in my case, I tend to prefer the older macro lenses to the new ones - in particular the 60mm AFD to the newere AFS version.