We have a request from a new potential user to use some font other than comic sans.  Any chance of that?

In the latter versions of Firefox, in its options, you can choose the fonts you like, and then uncheck the checkbox saying (sth like) "Authorize sites to use their own fonts"

Another possibility would be to install "Stylish" plugin - which you can use to re-design any site with your own fonts / colors / etc... (for more advanced users, but you can easily find loads of global styles uploaded by the community and then use those ones, or start from those in order to create your own style)