In north-western Ontario, my nearest Apple store is in Winnipeg, a 5 hour drive. There is also a Best Buy in the same area. I have a tentative plan to take March 25th off and drive there as something fun to do (and my spouse can do some shopping at Polo Park). I certainly don't *need* an iPad right away, but I'm off to a big convention in Indianapolis in the middle of April and based on previous experience with the Apple online store it would be close if I ordered through them.
A post on the Best Buy website mentioned that not all stores will have stock and the ones that do have stock get their shipments on Friday evening, so it would be Saturday before iPads would be sold.
I would like to know if Future Shop in Canada will be selling them. There is a Future Shop in Thunder Bay (also 5 hours away) and I will be going to TB for work the week after the launch, so that would be my backup plan.
In a country the size of Canada I really think preorders are a sensible policy. Who wants to commit to a long trip if they are not guaranteed to get the product? One benefit of the later Canadian launch date is that we will have some idea of the lines from the US date.