Firefox 3.5 and Epiphany crashing since the GNOME 2.28 update

[Curly Brace]

Hi all, I'm on 8.0/amd64, and my GNOME 2.28 update went off with no
problems, but now Firefox 3.5 and Epiphany 2.28 crash when visiting
certain pages, such as the "Welcome to firefox" first-start page.
Firefox leaves "Segmentation fault (core dump)" in the console when it
crashes, and Epiphany is silent. I've removed the Totem 2.28 plugins
(thinking them to be the cause), removed Moonlight, removed Java,
removed nspluginwrapper Flash10, and finally
removed /usr/local/lib/browser_plugins altogether.

This seems very similar to the Firefox 3.5 HTML5 <video> crash FreeBSD 7
users experience until they kldload sem, but I'm on 8.0 and sem is
loaded by default. I didn't 
see anything new in UPDATING, and I successfully played an Ogg Theora
video from an HTML5 <video> test page located at
http://www.double.co.nz/video_test/test1.html, so I don't think that's
it.

Is there anywhere else where browser plugins lurk, or is there anything
else the two may have in common besides plugins?