Recap: I like crisp fonts and hate blurry as well as ragged ones, so I
use msttcorefont, arial (a font with good hinting) and disable aliasing
between 8 and 15 pt. This usually gives me beautiful and crisp fonts,
unless somebody breaks some of the font rendering libraries.
Last time it was the whole kde broken, today it's just
firefox/thunderbird (and probably other gtk applications but I don't use
any at the moment).
I'm referring to the application fonts themselves (menus, preferences,
etc.), the content is *not* affected, unless it uses a badly hinted
font, but that's what the ReFont extension is for ;-)
In the control center I can change the fonts for gtk applications and
it's taken into account, so that's not the problem. The problem is that
firefox and thunderbird don't use correct hinting.
I don't know which upgrade broke it, I restarted the pc today due to the
new kernel, so it has to be one made between the last time I restarted
the desktop (time unknown) and today.