Samsung has announced a 32 gigabyte solid state flash memory device. This memory storage unit could completely replace the hard drive in a laptop, while allowing big reductions in weight and increasing speed. The weight savings come directly from the smaller size and weight of the device compared to a hard drive, but because this unit uses up to 95% less power, the battery in a laptop with this could be much smaller as well. And the laptop could be thinner, too.
It just won't be cheaper. The devices are expected to debut at $700-$1000, making them a luxury item, but they are still cheaper than the current generation of such devices, which cost $5000 or more. However, once they start to show up in consumer devices, the cost will drop quickly.
They are also good candidates for things like Tivo and similar DVRs, which have a high failure rate. People stick the DVR on top of the TV or on top of a stack of other boxes (DVD player, VCR, etc.), where the high heat kills the hard drive. Flash memory tolerates a wider range of operating temperatures, and would eliminate the most failure prone part of computers.