How Can I Improve the Font Rendering In Firefox

I've had this issue for ages, maybe it's time to do something about it!

It comes done to ClearType, Microsoft and patents from what I read. Most *nix distro's disable any patent protected font rendering by default.

Read about Debian and fonts here, you want Subpixel-hinting and Font-smoothing section.

There's a config file on that page but I will add here for future reference. Create a file called .fonts.conf in your home directory, and add the following:

<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
 <match target="font">
  <edit mode="assign" name="rgba">
   <const>rgb</const>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hinting">
   <bool>true</bool>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hintstyle">
   <const>hintslight</const>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="antialias">
   <bool>true</bool>
  </edit>
 </match>
  <match target="font">
  <edit mode="assign" name="lcdfilter">
    <const>lcddefault</const>
  </edit>
  </match>
</fontconfig>

These sites use Helvetica as their font. On most Debian systems it's not an outline font, but raster one. You can disable bitmapped fonts as the last stage of font configuration dialog:

$ dpkg-reconfigure fontconfig-config