When I bought my 10D, I still had my EOS 650 with a 35-70 Canon lens on it. That lens was acceptable for about a day and a half before I realized it was not the hot setup on a 10D.
In fairly rapid succession, I bought the 28-135 IS, and then the 75-300 IS. I was quite satisfied with those lenses for a few months, but longed for more wide angle. After an unhappy experience with a Sigma 17-35 EX, I bought the Canon 17-40L and was really impressed with the picture quality. Then, I bought the 400 f/5.6 L after being offered a deal I couldn't pass up. Within hours, I'd taken some of the best pictures of my life, and I was absolutely hooked on 'L' lenses.
Since then, I've bought the 24-70L, the 70-200 f/4 L, and the 100-400L IS. I'll consider the job finished when I get the 70-200 f/2.8L IS, hopefully before next spring. The odd thing is, I have focal length duplications, and that will be even greater when I get the 70-200 f/2.8, but I can't bring myself to get rid of any of them. I suspect the first three lenses will end up on ebay, but it will be like selling family members. (which, in certain cases, is not a totally bad idea.)
Tom
