And here I was thinking I was crazy. Back in November 2007 I made a post regarding memory errors I'd been seeing while using the latest version of Intel's GM965 display drivers on my Dell M1330. I was able to correct the errors by reverting to an older driver.
Looks like I wasn't the only one. Over at Intel's software developer forum, user 7oby created a detailed thread describing the symptoms of the bug, and the driver versions it affected. The post includes a link to the release notes for the driver where the problem may have been introduced, though going over the list of changes, anything could be the cause.
The bug has also been identified by Blizzard's tech support for World of Warcraft, where it was shown to crash the MMO on Macbooks.
Fortunately, the problem seems isolated to certain models of Dell and Macbook laptops running the GM965 chipset. Apparently Intel has a new driver with a fix in the pipeline, and will be releasing it shortly.