The Inconsolata typeface looks incomparably better in Emacs with "slight" hinting, but other faces, particularly Linux Libertine O, which I use everywhere that I don't want a monospace face, really needs hinting. What to do? I added
<match target="font"> <test compare="eq" name="family"> <string>Inconsolata</string> </test> <edit name="autohint" mode="assign"> <bool>false</bool></edit> <edit name="antialias" mode="assign"> <bool>true</bool></edit> <edit name="hinting" mode="assign"> <bool>true</bool></edit> <edit name="hintstyle" mode="assign"> <const>hintslight</const></edit> </match>to my /etc/fonts/local.conf, and then set Gnome's hinting back to "full", and then cycled Emacs through a font change so it would pick up the new setting. That worked for Emacs, but not for gnome-terminal. Apparently Gnome programs make gnome-appearance-properties settings override fontconfig settings. There's a bug filed about that over at Canonical, not that anything's been done about it:
At least Emacs and my Linux Libertine text look good. I have given up and switched to Deja Vu Mono for my terminals.