Font is messed up in web browsers (Safari and Firefox). How do I fix this?

I have an iMac and I haven't downloaded any new fonts (that I know of). Both Safari and Firefox display a font that's real skinny and all bunched together. It's definitely readable (it's not symbols or anything) but I have to look close and squint my eyes! It's so annoying! The only new thing I have done is I installed the new Firefox 4. But I don't know why this would affect Safari..? I turned on my computer in Safe Mode to see what would happen and it actually fixed the problem. But once I started it in normal mode again, that font came back. Please help! Sooo frustrated. Thanks!

Your screenshot is not viewable. However, run your Font Book.app from the applications folder and validate the fonts you have installed. It may be that you have a bad or corrupt font that was recently installed.

Validate didn't work, however, I just found the font that was displayed in Safari and Firefox and disabled it. I'm perfectly fine with that. It was Alien League...in case you wanted to picture what I was looking at! Thanks!