It turned out to be coincidental that this bug showed up on my system at the same time that the -9 version of the xfree86 packages were released. It turns out that you must not use the "--force-tls=classic" switch with the nvidia package install for a clean install AND use the 2.6.9 kernel. Apparently this switch will only work on 2.4.28 kernels with Debian/Sid.