Dear Andrew, you have to think again concerning IE-6.
Because majority of southeast europe, middleeast, africa and parts of asia do actually use IE-6.. I am pretty sure that all of the dolphin based sites that do refer to those regions got most visits from ie-6 browsers.. most, maybe all of the dolphin #owners# use most likely ie7+ or mozilla/chrome so in your websites statistics you will not figure out the importance but in the statistics of the sites that refer to those regions it is very obvious see more that most visitors come from ie 6..
My members forexample are from southeast europe/middleeast and i got 87% visit from ie totally 60% of those are from ie-6, 15% from ie-7 and about 12 from ie-8