In Opera 10.5 they added some features to browse more speedy than before with a new JavaScript engine, Carakan, and a new graphics library called Vega. Both should improve browsing speed, with Carakan being as much as 7 times faster than the Futhark JavaScript engine used in Opera 10.10.
Opera has increased room for content on your screen by replacing the menu bar with the menu button. The new version also integrates with Windows 7. It lets you access your tabs from task bar.
This new version will allows you to browse privately either in a tab or a separate window.
You can download it freely from official Opera site, and you can see the changes in this new version here. And you can also download it from Torrent if you have a Bit Torrent client