Some New Features:
Faster: Especially with scripts
Web Slices: Alerts you when changes occur to sites
Improved Search Box: There are now images in your Search Box and it Auto-Fills
Accelerators: Similar to Data Detectors for OS X folks
Tabbed Grouping: Group your tabs
Compatibility View: Downgrade to 7 for certain sites
Address Bar: Auto-fills based on History, RSS Feeds and Favorites
inPrivate Browsing: Activities, History and Cookies are not used when enabled
Reopen to last session: Similar to the same feature in Firefox
Suggested Sites: Search for sites similar to those in your browsing history
Overall I found IE 8 to be, well, not much like a Beta. I only had one crash during my first round of testing. It seems much closer to RC than a Beta. The new features are nice, but most are similar to features already present either natively or using plug-ins with other browsers. It’s got a new glassier look and feel and it’s definitely faster. But I’ll have to augment my own workflow before I can really harness many of these new features.