@Robert Gentel,
This is written using IE and XP.
I have the opposite results. I just switched over to IE and find the fonts much much easier to read. They are darker and the outline of them doesn't have that gray shadowy effect that it has in Firefox.
I'm going to switch back over to Firefox in a second and edit this to tell you the results of zooming in with Ctrl +. When I'm in Firefox and zoom in the view, the fonts have much more clarity and contrast.
This is written using FF and XP.
Edit: When in default view while using Firefox, the fonts are very faded as if, as you described, there isn't enough ink in the printer. However, when I use Ctrl + to zoom in, the fonts suddenly darken as if they've been bolded, have more clarity and are larger. When zoomed in, there is no difference in fonts between IE and FF. If not zoomed in, there is a big difference.