Just to tie up the loose ends, I found this:
Some folks are experiencing blurry font with the new FX 17. Basically, FX 17 isn't recognizing their "Clear Type" setting.
https://bugzilla.moz...g.cgi?id=814101
Mozilla fixed it right away so that future versions will be fine. But in the meantime, you can use this manual fix:
Enter about
:config into a Firefox address bar.
As always, click through the warning message.
Type gfx.content.azure.enabled into the search box at the top of the page.
Double-click the entry to change it from True to False.
Restart Firefox
Update: 17.0.1 released today (November 30th) to address this bug.
Seems to work in FF 19.0 as well.
Topic here:
Firefox 17 Blurry Font Bug - 17.0.1 Released - PC & Technology Help - Community-Feedback