As more GPU-acceleration features are made available and content that supports this feature it is increasingly beneficial even to average users to add graphics driver updates to their monthly maintenance routine.
Mozilla now also says that graphics driver updates are important to avoid browser crashes. "Firefox 4 brings many new features in the Graphics department, notably hardware acceleration and WebGL," Mozilla's Benoit Jacob wrote in a blog post. "However, when we turned these features on by default in nightly builds around September last year, and then in Beta 7, crash statistics and bug reports quickly showed that bugs in graphics drivers were often making these features misbehave."
I tend to be a bit pessimistic about graphics driver updates outside the professional and enthusiast segment of computing. There is a certain lack of education, especially in the mainstream market, that graphics drivers need to be updated on a regular basis. The mainstream user will need to receive a much better option for updated driver updates than what is available today. I wonder if browser manufacturers will, in fact, find a way to help users upgrade their graphics drivers as GPU acceleration seems to become an essential feature for web browsers.