Light Peak is probably going to be introduced as something that makes more since to call "Copper Peak", because, well it will have nothing to do with light, as it won't be using fiber optics. The fiber optic technology just isn't there yet, and it's also quite expensive.
That isn't the worst thing though, as Intel has Light Peak using copper going at speeds of 10Gbs, or about 1.2 GB per second! Pretty fast! Still, it's no where near what they wanted to introduce a true Light Peak at: 50Gbs, 5 times faster, and later ramping up to 100GBs.
Still, at 10Gbs I'd be happy to upgrade

You can fill up a Tera-byte HD in about 13 mins with that kind of power.
Supposedly USB3.0 should max out at 5 Gbs, or 640 MB/s, but we aren't seeing anything near that yet.
So, this "Copper Peak" we are bout to witness is theoretically twice as fast as USB3.0 but.. once it makes the jump to true fiber optics it would blow USB3.0 out of the water, of course by then I'm sure we'd see USB4.0.