Driver issues may not necessarily affect all applications. Sometimes when revising the code they may fix an issue with a particular application but at the same time break something in an entirely different application. If these problems only started after installing the latest driver revision, then the new drivers are probably at fault. You can try reinstalling the current drivers and see if that fixes it, otherwise the only other option to fix the issues may be to rollback to an older version.
Regarding the blurry fonts in Firefox, check to see if morphological filtering is turned on in the Catalyst Control Center. For some reason that particular post processing effect can sometimes be applied to 2D applications and may be why your fonts are blurry in Firefox. As for F1 2010, my only guess is they did something in the new revision that may have messed up that particular game's lighting effects.