Citar:Main changes/improvements:

AutoSandbox – suspicious programs will be optionally run sandboxed
avast! WebRep – browser plugin for website reputation rating; a combination of data from our virus lab and community voting
Script Shield now even in the Free AV
Site Blocking now even in the Free AV
SafeZone – a special virtualized area for sensitive transactions (e.g. secure online banking) (paid products only)
Restore factory settings command (Settings -> Troubleshooting)
Automatic actions in the boot-time scan
New compression method in the installer makes the setup packages about 20% smaller.
Script Shield now functional even with IE8/IE9 Protected Mode
Sidebar gadget
Improved stability/compatibility of the Behavior Shield
Improvements in the avast! sandbox