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The only L I can recall recently being around $550 is the 70-200/4, and it's been more than a few years since that was the case. Circa '05/'06. (Though CPW has it at $550 with a rebate in late 2008.)
I bought a bunch of equipment in July of 2008 when the rebates were going on, that is what I am basing this on. I seem to remember the 17-40 and 70-200 f4 were about the same price at that time, that's when I bought both.
At any rate, electronics prices should go DOWN over time, not up. The only time a price of something like a lens, which does not change from year to year is when it is completely redesigned. Something like the 70-200 2.8 non-IS price should be going DOWN, it's an old lens at this point, it's R&D cost has been recouped and it's what is known in the business as a "cash cow", pure profit, less actual manufacture and distribution costs. Differences in the price of the dollar should really not make the price of these goods fluctuate so much. Look at the cost of TV's, blue rays and other electronics...