Even after using the Linux 2.6.38 kernel power regression workaround for those systems affected by the ASPM (Active-State Power Management) bug that was detected by Phoronix, some Linux users still don't have their netbook/notebook battery lasting as long as they'd wish. For some, Microsoft Windows 7 is still performing better on the battery and/or Ubuntu 10.04 LTS and earlier. As I've said, there's still at least a couple more Linux power regressions and other areas for optimization that I've discovered and still haven't yet publicly documented in full, some in part due to still analyzing what's happening.
http://www.phoronix.com/scan.php?page=news_item&px=OTYxOQ-- can't say I've had this issue but an interesting read.