There's a very interesting presentation from Alan Cooper at Agile2008 here - I'd encourage you to go and read it. In the past (particularly when reading The Inmates Are Taking Over The Asylum) I've been *really annoyed* by Alan - in particular with his view that developers are inherently incapable of undertaking interaction design, in quotes like

"[Programmers] struggle with this idea of making computers behave more like humans, because they see humans as weak and imperfect computing devices."

But I'm finding a lot I like in this presentation; maybe I've misunderstood him in the past, maybe he's mellowed or changed his mind:

"While interaction designers are pretty good at inventing user interfaces, lots of programmers and product managers are good at that, too."

I need to read it a few times and mull it over before I can give an impression of the whole, but there's some bits which get my bulb percolating:

1. The approach around slide 37, breaking product development into 4 stages, with the middle two (design/engineering) as agile, others as not. This implies iteration and change occurs in defined periods, not all the way through product development;
2. Slides on cognitive bias (as a driver for observing users, not just asking them what they want) reminded me of Duncan Pierce's skit on the subject at last years XP Day;
3. And the engineering phase sounds eerily like a development equivalent to the sketching which Mr Buxton advocates:

"You are going to write it twice anyway, whether the discarded first one is in tiny parts or one big chunk, so you might as well make the first time count for the max.   Brooks says that we will do things twice. I say we should acknowledge this truth and maximize the first time for understanding, and maximize the second time for efficiency."