If you can't find a valid reason to grab the latest update of the most downloaded Mozilla product here's one well worth it.
Firefox 3 supports the ICC (= International Color Consortium) standard which aims "to obtain a good match across color devices; for example, a video which should appear the same color on a computer, LCD monitor, a plasma TV screen, and on a printed frame of video.". The only other browser which supports the Color Management is Safari 2.
Unfortunately Firefox 3 comes with the Color Management feature disabled. In order to enable it you have to type in the address bar: about:config
Then type in the filter box that appears below the address bar: gfx
Double click on the line: gfx.color_management.enabled
Reboot Firefox 3 and you are done!
If you wish to check if the feature is enabled visit this page.
BTW: As I'm writing there have been downloaded 9,000,000 copies of Firefox 3 worldwide in little more than 24 hours! The World record attempt was largely achieved...