It wasn't the anti-alising on Linux, it was something else. Nevertheless, I think I've found a way to make the fonts looks as they should be on Ubuntu (and other similar releases like Kubuntu/Edubuntu/SomethingelseBuntu).
Thanks to Jeremy Zawodny's post, and then a post in the masterplan (this post is absolutely correct when it says that we take font rendering for granted on operating systems like Windows and OS X, and then think that the fonts on Linux are just different), I was able to figure out some ways I could make the fonts on Firefox in Linux look like the fonts in Windows or on Mac.
I won't steal the contents from the post in the masterplan, however if you too want to fix the font rendering and font display in your ubuntu install, then do head over to the 'Sexy smooth fonts on kubuntu' post and follow the super simple instructions (if you guys are stuck, then I'll try to help out here).
Furthermore, you might also want to turn on Subpixel smoothing with Ubuntu by clicking on System (in the menubar) > Appearance > Fonts tab > Choosing sub pixel smoothing and clicking close. And Viola, that's an easy way to make sure that you have the smoothing that's best for almost any monitor.
I think the reason this feature is not turned on by default is probably to save some system resources (you know how particular those uber geek ubuntu users are =) !), but nevertheless its super easy to do whatever you want in the operating system. Which, of course, is absolutely great!
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