There appears to be some kind of problem on at least Raring a Saucy Ubuntu's with its
pango-graphite package. Please see bug report on Launchpad.net for more details:
After upgrade from 12.10 to 13.04 beta of Ubuntu (Xubuntu), I am experiencing some issues. Like without me actually changing anything, my fonts are broken for some applications (most of them) and not for other (rxvt).
See this http://i.imgur.com/ubVvr53.png
As you can see, rxvt there is the only application with normal fonts. The Terminal application from Xfce suite is for some inexplicable reason using some kind of proportional font. See that the font in the Terminal Preferences is set to Liberation Mono. Also, please notice how in the Choose Terminal Font dialog the Courier New font Preview is not Courier New.