I've been reading as much as I can about Vista.
Out of curiosity, who is running on the 64-bit version and who is running the 32-bit version?
It seems that most of the driver and software problems stem from the 64-bit version. Most software and drivers being written in 32-bit. Some articles I've read also point to the processor in use, some 64-bit processors have difficulty in running 32-bit software, hence need patches or software downgrades (which kills the system speed). Apparently some run in 32-bit mode and have additional addresses for any 64-bit code that comes along - trying to find which processors currently are organised this way (seems to be AMD X2 chips).
I don't have a conclusion ... or really a point yet ... but as far as I can tell all of Vistas problems stem from incompatibility between 32 and 64 bit.
Either the processor is running in 32 or 64, the software is written in 32 or 64, the drivers are either 32 or 64 and none of them talk particularly well to each other.
It also seems that the 64-bit side of things can't read 16-bit applications.