On the main question list (main site and meta), I see this:
The questions are cut off at some narrow width as if something is overlayed on top of them. I have seen this in Firefox 3.6.9 on a Mac 10.4 and on 3.6.10 on Linux. If I click "questions" then everything is correct. I do have the ability to run DOM inspector if there is any more useful info that I can provide. But I can't seem to find which element is on top of the questions.
I was able to fix the problem in DOM inspector by deleting the overflow-x and overflow-y (!) CSS rules on the question-mini-list div. But I have no idea why that helps.