Marco Arment articulates much better than I did on why the Kindle Fire likely won’t affect iPad sales:
What we’ll see with the iPad depends on why people buy iPads. My theory is that there’s an iPad market, not a “tablet market” — that people want the iPad and specifically seek it out without comparing it to other tablets.
A “tablet market” suggests that people first decide they want a tablet, then they comparison-shop and choose the one that best fits their needs and budget, like buying a dishwasher. I don’t think we’ve seen any plausible evidence that a meaningful number of customers think of tablets generically like that.
But if anything’s going to prove me wrong, it’s the Kindle Fire.