A friend of mine gave me a Seagate Momentus XT 500 GB 7200RPM and I love it, its snappy and quiet. The only downside that I have noticed is that the battery went from lasting 5-7 hours to 1.5-2.5 hours. And I only use my MacBook for light things like web browsing and downloading music and some youtube. Nothing to hardcore. Anybody have any tips or anything? I have a 15-Inch MacBook Pro i7 2.66 GHz with 4 GB 1067 MHz DDR3.