Hi,
I've just noticed that, on Utopic, the default fonts for the GNOME
desktop are "Cantarell" (window titles and interface),
"sans" (application) and Ubuntu Mono (fixed). Wouldn't it be more
logical to whether use only Ubuntu fonts or only GNOME fonts
("Cantarell", "sans" and "Monospace")?
I'd go for all GNOME fonts, personally.