Thanks Karen. All of my macro shots are with the Tamron 180mm until I can afford a shorter one to add to the kit. I can't ever remember the exact setup but I do know it was with the TC and at least a 20mm tube if not the full 68mm (think it was just the 20 though).
I would definitely not go longer (unless you want to trade :biggrin: )
The longer lenses are much more difficult to light (I have to run a pretty large softbox) and are much harder to handhold shots. I'm looking at picking up an 85mm f3.5 macro because I honestly don't need the extra working distance 90% of the time. If they don't get scared off with me 12" away, they usually don't get scared off when I mis-judge and come withing 4-6" away.