This is going to be necessary for more than just hard drives. Lots of multimedia devices are going to start needing significantly higher bandwidth.
4K video (2x2 times higher resolution than HD 1080P), faster removable flash memory for downloading your 150 megapixel images (from the prototype sensor Canon just announced), etc etc.
Granted, most of this will be transferring to/from hard drives, but as several people mention blow, SSD HD speed is increasing. There's already a company that sells a PCI-E card with 16 flash chips RAIDed that can saturate a 10 gbit ethernet pipe.