There are changes and new features in several areas, but some of the most interesting for web developers are the new CSS effects: rounded corners, various forms of shadows, and providing fonts to use for text.
The Mozilla Hacks site has thrown all these together in a demo (which in itself looks hideous, but does succeed in showing what’s possible), and there are a few other articles on that site also worth exploring. They link to Font Squirrel, which seems to be a good place to find free downloadable fonts to use on web pages.
Often when a browser gains new capabilities web designers are understandably reluctant to make use of them straight away — understandably so when they lead to a worse experience in existing browsers.
The great thing about these new CSS features is that they degrade gracefully: you can specify your organization’s house font for body text (or whatever) so Firefox 3.5 users will see it, while users of other browsers will be blissfully unaware and continue to see your site exactly as they do today.
What do you think — let us know in the comments below. Are you going to use these new effects in your website? Have you upgraded to 3.5 yet, and if so are there any new features you find particularly compelling? And most importantly, have you found any pandas?