Well, the various covers and cases are not out yet, but one thing to really consider is AppleCare. With traditional AppleCare for $249, you get three years of coverage and if you use the right Amex or MasterCard, you get an additional year added.
But for a device that costs $4K, it might make more sense to get more coverage. Certainly, all my MacBook Pros have lasted way longer than four years and so AppleCare+ is now available as an annual subscription.
It is still cheaper to get it in the three year bucket, but for instance with the MacBook Pro, it is $249 for three years and $99/year forever otherwise, so if you love the thing and even five years from now you still want it good, this is not a bad option.
Of course by then, the MacBook Pro on current course and speed will have 1,000 cores and use 1 watt of power lasting a year, but you get the picture.
For iPhone and iPads, I’m not sure this makes as much sense mainly because the dollar values are lower so repair costs are as well typically. But, a new motherboard for a MacBook Pro is $800, so at some point it makes sense economically just to replace it (although that’s not as good for the environment of course 😉