Barry has just announced that there are three issue serious enough to delay the release, even though this potentially means slipping the release schedule (though time will tell whether that's a serious concern). If you are a Python developer, please take notice of what he said in an email to the python-dev list earlier today:
Quality is important. Please do whatever you can to help. Many people can benefit from a little extra effort now.Please everyone, if you have only a little bit of time to work on Python, I hope you will attack the release critical and deferred blocker issues, and work on turning the buildbots green. These are the top priorities in order to get 2.6 and 3.0 out on time. And just as added incentive, our October 1st goal is being noted by downstream vendors. [Possibly confidential information about third parties redacted].