I think the critical portions of their design have been Jobs-driven for quite some years now. A friend of mine, now an Apple emeritus distinguished engineer, s

I think the critical portions of their design have been Jobs-driven for quite some years now. A friend of mine, now an Apple emeritus distinguished engineer, said that during the engineering redesign of the Apple UI elements for Leopard (10.5) (which ended up looking nearly the same as 10.4), the engineers would have a weekly meeting, where they'd present just a few buttons. Jobs would walk in and say "yes" or "no" and walk out. Took quite a few iterations. ;-) (To be clear, this was the internal re-engineering effort to make the Aqua UI resolution-independent. Inside of 10.5 is a huge set of tools that accomplish that fact, but it still had to look the same at current resolutions, and also look good at higher, which we haven't seen yet. The good results is that they can deploy a whole new system-wide, resolution-independent look & feel by replacing some XML and PNG files in the Appearance internal framework, and with no code changes. I suspect we're going to see that used in 10.6 very late in the cycle so there are no leaks.)