Bought a 17" Macbook Pro in November 09. Good stuff, I used it a lot but it wasn't fast enough for my needs so in January or Feb of 2010 I picked up a 27" quadcore iMac, amazing, I highly recommend them. I used the new iMac so much I almost forgot about the MBPro leaving it on the charger all of the time. I had heard that this was ok to do and wouldn't stress out the battery because the new chargers were "smart". Big Mistake. I used it maybe three times since January and now instead of getting the 8 hours I used to on battery saver mode I'm getting about 3.5 hours (battery says it's at 95% health which doesn't make a whole lot of sense.) Would it be better to let the battery completely drain down and leave it off of the charger until I need it? Just wanted to make everyone aware of this.