I have the newest 17" MBP and consistently get about 7-8 hours on a charge. I noted this from the very beginning. I've had it now for about 3 months. I have multiple apps running including web browsing. Of course, when I use Final Cut Studio to edit a piece or do foley work, battery life is shorten. In this case I simply leave it plugged in. I would suggest returning yours to Apple to have them look at it.