$ rpm -q firefox gtk2 pango cairo firefox-1.1-0.2.5.deerpark.alpha2 gtk2-2.7.4-1 pango-1.9.1-1 cairo-0.6.0-1.1 (cairo-0.6.0-1.1 is actually 2005-07-29 CVS, to avoid the crasher.) Firefox renders fonts differently than other GTK2 apps, most noticeably in the titlebar. The attached xmag screenshot shows it best - firefox is on the top, liferea on the bottom. Looks like firefox isn't using subpixel AA, while other apps are.
Created attachment 117317 [details] xmag of two titlebars
We just updated the Firefox version in Fedora/development from 2.0 to a 3.0 pre-release version, which improves performance, memory usage, and fixes many bugs and crashes. Closing as CANTFIX since we aren't fixing bugs filed against 2.0 now that 3.0 is in. If this bug is still present in rawhide using a Firefox 3.0 version, please re-open this bug. Thanks and Happy Holidays