Twice the speed is great. But at what price? Three or four times? Ten times the price? More? I think Thunderbolt (Intel) to consider "value position" not this "I only have to sell one!" mentality. While there's a prestige factor of driving the Carrera thru a school-zone, there's always some bottleneck somewhere that restricts speed.
The killer-app for home/indiv use of the highest speed could be System Backup/Restores, but how often would that be used? Once a week? A month? I think a lot of folks do slow backups now and go get lunch, or leave the system running overnight. It consumes a lot of machine-time therefore but very little human time. If the backup was stripped from a 4-hour time-frame into 30 minutes, that'd be great. But I'd still not sit there and watch a machine whirr for 30 minutes. I'd get up and do something else.
Would Video be greatly improved by a data-thruput four times faster than USB? Well, the 4k and 8k videos might need this bandwidth to achieve interactive video.
Or maybe when the KGB opens up all of their vaults to Snowden, he'll be able to get THEIR secrets much faster working with Thunderbolt. I can hardly wait. The KGB have always been soooo honorable in slaughtering tens of millions, and Snowden can learn so much about their history of humanity.