The question seems old but the topic is one that won't die over time.
As a former Nikon fan in film area who saw the real light through the L series glass and now a total Canonist
I find the best deals on ebay and from other on line major sellers when they come with their too good to be true deals (With double emphasis on Major sellers such as Dell etc and not the ghosts from China or elsewhere where disappearing things especially the money is their specialty). I have had several accessories bought from UK sellers on ebay and found the price, quality and shipping quite fine. Some of my big lenses from Japan where the real steal as well. In short on-line buying is my preferred mode and yet to see any local shop, even those who sell both on-line and locally, to match the on-line prices.