I will go back and do that list of 'things I use in Vista every day that make a big difference to me' but for personal reasons (I've been ill, my mum is ill, we've been travelling, there's a lot of work to do and other irregular verbs) I haven't got to it yet. But if you want the deep technical differences, the first two articles by Mark Russinovich on the Vista kernel are online at http://www.microsoft.com/technet/technetmag/issues/2007/02/VistaKernel/default.aspx. That includes things like not switching to a new thread if the current thread hasn't had a full execution cycle (which is like taking away my plate when you clear the rest of the table even if I only just sat down and everyone else has had half an hour to eat, just because you clear the table every half hour) or giving different priorities to different memory allocations (so indexing has to back away from the memory and put its hands in the air when you want memory for running an application). Every time you Boot Vista it takes a look at what was slow and makes notes for how to try to be faster next time.
The second article also explains: where your memory is going and why you don't need to worry that it's not showing up as 'free' why you don't have BOOT.INI any more how to see startup process connection in Process Explorer so you know whose program is whose
This isn't tweaking information unless you're a developer, but you can see the extra levers and knobs Vista gives developers to twiddle. Plus, understanding some of these changes might give you the confidence to sit back and let Vista manage memory and schedule cpu priorities without trying any of those idiotic tweaking utilities that mess around in the registry ;-)