Web slices, aka automatic feed updates. If these are turned on, IE8 periodically checks online for updates to specific feeds, much in the same way you might check for RSS feeds for blog posts. IE8 doesn't have to be running for these online checks to occur. A great example would be to monitor the status of a bid at eBay without having an eBay browser window always up. Slices display in your Favorites Bar, and when the item has changed, its text becomes bold.

The new SmartScreen Filter (an enhancement to the Phishing Filter) and Compatibility Views, as well as cool features that combine only when working with Windows 7, like Jump Lists and Windows Touch.

Firefox 3.5 beta 4 touts increased performance and stability with the new TraceMonkey JavaScript engine (where Firefox needs to outdo Chrome and ), support for native JSON and Web worker threads, and new Web technologies like HTML5 video and audio features, all of which have developers' mouths watering. I'm confident Firefox will be a solid contender to continue challenging Internet Explorer in the browser wars.