Thanks again for the comments, folks. I must admit, although I love the 100mm macro for many reasons, I'm considering replacing it with the 180L. There have been many times recently when I have really craved that narrower field of view and longer working distance that the 180L provides, and I'm not really bothered by the fact that I'll need to use a tripod to get the most out of it. I have been trying to use the 200mm f/2.8L to that end, but the maximum magnification is a hair below 1:5, and that's just not cutting it for anything but larger flowers. My only real concern is that the 180L is so dang expensive! It seems like it should not cost that much more than the 100L...
