I can confirm this 'bug'. I had a closer look and the incriminating font seems to be 'DejaVu Sans, ExtraLight' (e.g. use memstat |grep fonts). On a laptop I get in a default configuration (clean dapper, new account, fontconfig default answers - native, automatic, no bitmap fonts) a very light and fuzzy rendering (font rendering set to best shape). In case I switch on subpixel-rendering I get even blurrier and colorfull fonts. I can provide screenshots etc. in case it is necessary. Best way to confirm this is: 'gnome-font-viewer fonts:///DejaVu%20Sans%2C%20Ultra-Light'. I have no idea if this is a fontconfig bug or a quality issue with the font-hinting. Other DejaVu fonts do not have this issue.
Actually monodevelop is using the following fonts. I think the vera-ones are probably not intentional too. 132k: /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-ExtraLight.ttf 11244 144k: /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono-Bold.ttf 11244 152k: /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono.ttf 11214 11244 196k: /usr/share/fonts/truetype/ttf-dejavu/DejaVuSerif.ttf 8363 11244 68k: /usr/share/fonts/truetype/ttf-bitstream-vera/Vera.ttf 11244 60k: /usr/share/fonts/truetype/ttf-bitstream-vera/VeraBd.ttf 11244 -- Fuzzy Font Rendering https://launchpad.net/bugs/43105 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs