Some more food for thought:
I tried using the older (4363) drivers instead, and it only got worse. In this case, I got exactly the same results as before, only now in the one case where I expect things to work, they don't. Instead I get the NVidia logo, followed by a blank white screen with the mouse cursor. Sounds like that problem the other guys were having, no? Only my screen is frozen at white, not black.
Also, you said:
Windows can correctly initialize the graphics card, Linux can't
This struck me as wrong at first, as I was fairly sure I could do the following: cold-boot into an older kernel that doesn't have the nvidia dirvers installed on it causing X to fail when entering init level 5 (the XF86Config still points to the nvidia drivers). Then do a warm reboot into the latest kernel which has the nvidia drivers installed. This, I thought, should make it work without having ever loaded Windows.
I just tested exatly that, and it appears I was wrong. It does not work. So what the heck is Windows doing that Linux is not? And again, is this a problem with ACPI (kernel level) or the video drivers? Is it perhaps time I visited the ACPI4Linux forums?