I've seen lots of MacBook battery life questions, and I came into possession of one recently, so I kept a log, which I'm publishing now for your amusement. iBook 2GHz C2D with 4GB (3.3GB available) and 160GB HD. All usage was general wireless surfing and IMing... All figures were running the battery down to shut-off point. 15 cycles: Default: 3h 22m 4h 12m 4h 08m Turned off bluetooth, switched from 1GB to 4GB: 4h 30m 4h 19m Made custom profile for screensaving and powersaving (basically, never shut off, make screen go dark in one hour) Also, at this time, I calibrated the battery, by letting it run flat, then leaving the macbook until the battery was COMPLETELY dead (took 16 hours) then gave it a full charge and left it for 8 hours trickle charging once completely full. 4h 55m 5h 12m 4h 48m 5h 01m Then I started dimming the screen. I often use my laptop in low light or well shaded areas, so I would set the screen to a comfortable medium setting. 5h 46m 5h 35m 5h 37m 5h 26m Then on the dimmest setting (2nd lowest) 6h 52m 6h 59m This is not using iTunes, or any DVDs, but may have included watching 1 or 2 youtube videos. In summary, turning devices off that you do not use does help, but the greatest saving comes from the double-whammy of dimming your screen and not doing anything processor intensive. I'm currently on battery for 2h 10m and have 4:10 remaining (66%) I hope the above figures are useful to anyone else curious about battery life on the current MacBooks.