The look and feel of web pages in FireFox in Ubuntu (possibly other Linux distros) by default stinks (in my opinion). Trying to convert myself from Windows solely to Linux, this has been hard, but I found a way to make the fonts look really good in Firefox (improves the entire experience):
Change the fonts in preferences:
where it says, serif, select 'Bitstream Vera Serif'
where it says, Sans-serif, select 'Bitsteam Vera Sans
where it says, Monospace, select 'Bitsteam Vers Sans Mono'