Since yesterday's update, there are numerous reports about 360s being bricked. Some people suspect that this is being done by Microsoft intentionally to stop modders and hackers. Xbox Scene thinks it has more to do with certain combinations of hardware and firmware. That would explain why some people are reporting problems even with new, unmodded 360s. Other readers have informed X360F that they are unable to even complete the update download itself. Since the update can't complete, the 360 won't even allow users to play offline games for "security" reasons. It's worth noting that Microsoft is definitely aware of these issues.
Having heard about these problems, we tested our own 2005 360 with a few levels of Lego Star Wars II -- purely for research, of course. So far, we haven't encountered any problems since the update. How about the rest of you? Any bricked or otherwise nonfunctional 360s out there since yesterday? Leave a comment here and let your voice be heard.
Update: Microsoft has released a new version of the update that should behave with all console configurations now. If you've been afraid to update, it should be safe now. Those whose consoles have already been wrecked are advised to call customer support. Click here for more details.