To me at least, your "constant" attachment to your iPhone is why you'll want the iPad.

I think this is the iPad use case:

In the living room, it's there as a digital photo album until that moment you decide you want to get online. It has a job, it has a place, it isn't just clutter. You're going to keep your "main" computer be it laptop or desktop. This is just going to be the most convenient option because its bigger than your smartphone/iPhone/iPod Touch, and (I expect) more satisfying than your netbook because it's more responsive.

In the same sense that all technology adapts and changes, sure. I don't think it will "fade" so much as undergo a near-continuous transformation.

The iPod didn't really bring anything new to the table, it did it "better." It found acceptance with a bunch-o-people on its merits. I expect the iPad is going to find a lot of acceptance and use with people at large because of the design choices made --not in spite of them.

This misses the point of what Apple's trying to accomplish here (I think). To me, it seems the iPad is aimed at very routine, high frequency activities that happen in the living room (and sometimes when you're out and about) that the current line-up of household tech doesn't address well:

1. When I get home, put down the bags, and settle down to relax, I want to read: iPad.
2. When something strikes me that I want to do a quick search on or read online, if my laptop is still in its bag: iPad.
3. I want to make a recipe I found online, I don't want to get flour on my laptop keyboard, I don't want to waste a sheet of paper, I don't have a lot of counter space: iPad.
4. I'm sitting with the wife and she's watching something I don't care about, so want to listen to music and do some light browsing: iPad.

Q: Why do you think it has a digital photo album mode? A: So it won't look awkward sitting in the living room.

The thing is when I want/need real power, I go to my laptop/desktop/REAL PC. When I'm living the rest of my life, I want to go to something like the iPad. It helps define the boundary, it nails the UI, and its really accessible to the rest of the house.