While reading (1) further, I bumped this: "Running the mixed setup on a workstation is not recommended, because iptables, the XFS filesystem, non-free NVidia and ATI binary drivers do currently not support it." 'mixed setup' there is 32bit apps with 64bit kernels. So this might concern me directly.This is strange as I am using the Nvidia drivers on my 32 bit sid with a 64bit optimised kernel, albeit self compiled.
Ok in search of clarity (or maybe sanity) I booted my 32 bit sid and installed a 2.6.8 -k8 kernel (from sarge) to have a look at the /boot/config file to see if there were any differences with my Kernel config. Unfortunately, my config, whilst specifing a K8 processor type, is still x86_32 while the debian one is X86_64. I failed to appreciate that there was more to making a kernel 64 bit that changing the processor type to K8. Sorry, it would appear that mixing 32 bit apps and 64 bit kernels doesn't seem to like the nvidia drivers after all.
In fact there doesn't appear to be any amd64 kernels in sid i386 anymore. Maybe for this reason?
Sorry for leading you astray! Wackojacko