$30 for 6GB is a joke. Don't get me wrong, its approaching fair (we pay less for 60gb home internet) but what in the world would drive me to blow 30 bucks to browse webpages on modem-like speeds (25-35 secs to load a page), not to mention the poor 3G coverage in Canada?
Personally I think its absurd. I'm wanting the iPhone for its wifi, I couldn't care less about 3G and Rogers' laughable plans. Maybe if they offered a $6 for 1GB data I would do that, just for the coolness of it.
I'm going to just get the cheapest voice plan available and as stated earlier, if they do lower their data plans to a reasonable amount, I may just go for it, but until then - no thanks.