While we're still a ways from having affordable flash drives en-masse, hybrid hard drives are nearly at our doorsteps. Yesterday, Samsung announced that they have begun shipping the first hybrid hard drives to a few OEM's, with retail shipments coming in the near future. The first drive, the MH80, will come in 80GB, 120GB and 160GB capacities and sport either 128MB or 256MB of on-drive flash memory. While not used for any sort of permanent storage, the flash memory is ideal for use in write caching and will save large amounts of power by not having to spin up as often as a typical hard disk.
According to the article, the 70 to 90% reduction in power will result in up to an additional 30 minutes of battery life, which is quite a significant gain. It accomplishes these reductions in power consumption by writing data to the disk in larger bursts, rather than continually keeping the disk at ready or spinning it up and down several times a minute. This should also have the side effect of prolonging disk life, with reduced wear on the mechanical components. This technology is definitely exciting, though I hope it pushes true solid state hard disks even further along.