Many iPod classic owners are reporting that the update to firmware v1.0.2 is causing their hard drives to spin-up continuously after using Coverflow, others report that the spin-ups are constant no matter what mode the iPod is in. This is leading to extremely poor battery life, some claiming as little as 3 hours of music before the iPod forces you to recharge, as well as an increased risk of hard drive damage.

Hard drives are fairly damage resistant when parked, but when spinning up to read or write data, a sharp bump can cause the head to hit the platter and the drive be seriously damaged or even destroyed. Apple has not yet commented on this issue and there is no known fix. iPod classic users are advised (by me) not to update to v1.0.2 until this problem is resolved.

Read more here.