I just installed firefox 3, and yes, I can see there's a few things going wrong on a couple of pages. Nothing that makes the site unusable, but its still a pain. I'm gonna be fixing stuff next week.
Apparently, it has to do with the way Firefox 3 works with layers or something. I tried to look it up a bit.
A quick and easy way to highlight everything at once is Ctrl+A.
You can also fix it by going to Tools>Options>Content>Colors and then deselecting to let pages use their own colours, but then everything looks plain and not fun.
I see what you mean with the whited-out text. I'm on Firefox 3 as well, but I just assumed that the pages were supposed to look like that. *smacks herself in the head* ... But thanks Gebusa, I actually didn't know I could change the colours on the screen.. but I think I'll stick with the normal outlook.