I hate that poll. The only reason the 100mm macro has 53% of the vote is because it has Canon on the side, and it's a good length. YES, the Canon 100 is a fantastic lens, it probably the best choice for many people for general macro photography, but it does not mean it is the best macro lens, nor the best for certain situations. I'm not dissing the 100, nor am I saying if the 100mm length is right for you, that you SHOULDN'T get the 100 macro. But I think that getting it simply because more people on this board have it than other lenses is not the reason to buy a lens.
IF you need internal focusing, AND the 100mm length, AND USM, it's the best bet. If you only need the 100mm length, you should probably save a few $$ and pick up a Tamron 90, Sigma 105 or Tokina 100. If you need a more compact lens, that's full frame compatible, get the Sigma 70. If you need a compact lens, and you DON'T need full frame, the Canon 60 is a good bet. If you are shooting a lot of insects, or need more working distance, the Sigma 150mm is a fantastic bet. If you need even more working distance, the Canon 180, Sigma 180, or Tamron 180 all will do the job.
I.E....pick the lens based on your needs, not on popularity. The lens most people probably own on this board is the 18-55...it doesn't mean it's the best. 