you don't need the hood for it. Especially if you'll be using it for Macro mostly.
Very true... I have the lens and never use a hood for macro and rarely use one for non macro shots.
If you feel you do need a hood with this lens, I have a suggestion. The suggested hood for this macro is the ET 83B II, rediculously priced at about $44. The few times I needed to use a lens hood with the 100mm, I used the ET 67B which came with a used 60mm 2.8 I purchased. The ET 67B works fine and its about $25.
Also, I find I get great macro shots using a cheap monopod. No need for IS.