Just surfed to Opera.com to check if 9.0 has been released yet and noticed an upgrade to 8.51 has been released ...announced and downloadable at [opera.com...] .
Looks like an important security upgrade for 2 vulnerabilities (a "Opera Macromedia Flash Player SWF Arbitrary Code Execution" vulnerability on Windows and "Opera Command Line URL Shell Command Injection" on Linux), both of which are rated "Highly Critical" at Secunia. Upgrading mine now - would recommend that everyone does the same.
Thanks for spotting this futuresky - I see in both cases the bugs were not directly with the Opera program but with associated plugins (the Flash plugin) or scripts (the Unix/Linux startup bash script). I was slightly surprised that you need to download a completely new version of the browser just to fix these two problems, so I checked the changelog and there appear to be some other miscellaneous bug fixes added too: