Opera now comes in 64bit for Windows and Mac. Be sure to click on "more options" on the download page if you want this version.

Opening Opera with multiple tabs is now a lot fast. Opera will load visible and recently accessed tabs first to reduce lag.

Hardware acceleration/WebGL and better HTML5 support have been added. You can try those fancy new web features everyone likes to talk about.

Unity and Widgets are now disabled by default and Opera Voice was removed.

For a full list of changes please read the changelog:
http://www.opera.com/docs/changelogs/windows/1200/

http://www.opera.com/

This update includes a brand new rendering engine. Websites load faster with better compatibility.

Check the Opera website for more details.
http://my.opera.com/chooseopera/blog/2011/12/06/a-shiny-new-opera-11-60
http://www.opera.com/browser/new/

Major new features are password syncing with Opera Sync, Speed Dial Extensions, and a new Presto rendering engine, plus more.

Changelog:
http://www.opera.com/docs/changelogs/

Desktop Team Blog:
http://my.opera.com/desktopteam/blog/2011/06/28/swordfish-jumps-out-of-the-water

In addition to what was already mentioned for the beta (WOFF, CSS3, Speed Dial Improvements, etc), Opera greatly improved OperaTurbo by replacing the old JPEG compression with WebP compression and other improvements.
http://my.opera.com/chooseopera/blog/on-a-horse-opera-turbo-to-the-rescue

Download at Opera.com ( http://opera.com )

New features include added support for CSS3 Gradients, new embedded fonts (WOFF), and WebP image support.

Major Speed Dial improvements. With the ability to add an unlimited amount of sites.

Opera can now auto-install Flash Player without the need to restart.

More importantly, a speed increase! Yes, it's possible for Opera to be even fast.

Read more:
http://www.opera.com/browser/next/
http://my.opera.com/chooseopera/blog/barracuda-released-from-holding-tank