I've noticed that when I apply some visual styles the font in firefox goes kinda funky. Does anyone know how to change, or better yet, prevent this from happening?
I've noticed that too. The system-wide fonts (which includes most applications) can be changed (or reset) by opening up Display ----> Apperance ---> Advnced. There you will find a drop-down menu where you can change fonts for different aspects of the visual style. Make sure you keep the original dimensions of the object on which the font sits. For example, if you change the titlebar font, make sure you keep the titlebar at it original dimensions.
Only ttf font works system-wide. Firefox doesn't support those non-ttf font like .fon font. So, try to use true type font and you should have no problem with firefox display.