I got a screenshot from a client viewing the same site in IE7 and in Firefox 3.6.12 and (amazingly) the fonts look better in IE7. We are using typekit for the bold/subhead fonts which is fully supported in Firefox. Is the reason for the "bitmappy" looking fonts a setting in firefox which disables the font smoothing option on windows-based computers?
I've noticed this same thing. Not just in IE7, but IE in general has better font rendering than Firefox. This could be the only positive thing that IE has going for it!
Both browsers DO have options to edit the default fonts, but sadly they have no font smoothing options. Mozilla's just going to need to hop on the smooth fonts bandwagon I guess ;)
Another thing to check out is how the fonts look on a Mac computer. I've found that especially with bolded fonts, the text is bigger and smoother on a Mac. This can cause some layout issues especially in navigational areas where the links are arranged horizontally and should fit onto one line.