In my opinion, the feature in IE7 Beta 1 that separates it from the rest of the web browsers is the all new phishing filter. 99 out of a 100 times, "you" know that those "update your paypal/ebay account" emails are bogus phishing sites – but millions of other people who surf the internet everyday don"t realize this. Phishing has become an epidemic on the internet, and the average person has become used and abused because of phishing.
Although the Phishing Filter is not in Vista Beta 1 (it will be incorporated into future releases), it is in Internet Explorer 7 Beta 1 for Windows XP. When your web browser navigates to an address, IE7 will (just as normally) connect to the web server and download the page. While IE7 is downloading the page, it generates an asynchronous call to a special database of phishing sites. If the database has the website marked as a phishing site, it will display a warning page instead of the actual page with options to close the window or continue to the page. If the page is not marked as a phishing site, IE7 will look at the downloaded page for things it determines phishing sites to have, and form an opinion whether the site is a phishing site or not. If IE7 thinks this is a phishing site, it will display a warning, and even allow you to report the site as a phishing site.
Ask the victims of identity theft how long it took them to get back to life before their identity was stolen - it"s clear that the IE7 Phishing Filter is a feature that will save people more time then any other feature in web browsers. It"s nice that IE7 has Tabs and RSS support, but the Phishing Filter has put IE to the head of the pack.