Here is some detailed info on the battery of my new laptop.. When I first received it on Feb 19th: I didn't turn on the laptop. Instead I went straight to the bottom and upgraded the hard drive to a 500GB 7200RPM Seagate Momentus. I then plugged the laptop to the charger while using the laptop and let it charge to 100%. The battery turned out to be 12760 mAh. After using the battery on & off a few times by March 4th: Eventually after periodically using the battery on and off, two cycles completed. My battery turned out to have a capacity of 12819 mAh. Calibrating the battery fully for the first time March 10th (today): I used the battery last nite from 8PM to start the 3rd cycle. I set the brightness 2 levels below maximum. I surfed the web, chatted, read this forum, created auctions for eBay, had multiple windows open, and used iWork '09, etc. The battery lasted till 1:30 AM. So the battery in this format lasted exactly 5 hours and 30 minutes under these settings. I was never away from the computer for more than 5 minutes during this entire time period, and was using it pretty much the entire time without giving it a rest. The laptop shut off into sleep mode since the battery drained.. and I left it uncharged overnite while I slept to make sure any leftover conserved juice in the battery was drained too. I woke this morning, six hours later, and fully charged the battery. After this calibration the battery capacity turned out to be 12831 mAh. Over this entire period of ownership, the battery at full charge has been said to be at 100%, then ranging from 98 to 99%, and back to 100% now. I hope this information helped current and potential MBP 17 unibody owners. If you have any questions, feel free to post and ask here.