I noticed that while typing in the rich text editor in gmail, I could select a different font, but the font face remained the same. Actually the drop-down list showed all the font names listed with the same default font face. Strange. On a hunch, I downloaded the ttf-mscorefonts-installer package. Instantly (without restarting firefox), the fonts were now available. the drop down list now shows the font names in their own style. Is this a known dependency? If so, perhaps ttf-mscorefonts-installer should be a default package in LMDE?
Using Firefox 3.6.13
I'll see if I can uninstall that package and show the problem I had before.