I have been excited about Light Peak/Thunderbolt for a year or so now, but in that time it seems the ambitions have become smaller, and the competition has developed as well.
Edit: Whoa. I just re-read parts of the Intel documentation, and it seems there are indeed two independent downstream channels. My bad. It also looks like there is no provision for using both channels for a single device? I have no idea.
It lists 2560x1600x30bpp @ 60Hz as using just over 8Gbps, so any one consumer monitor will work fine over Thunderbolt.
The 17.28Gbps speed would only be needed for multiple monitors or a high-resolution, high-color-depth, high-refresh or 3D monitor. Thunderbolt and full-speed DisplayPort both have enough aggregate bandwidth for four 1080p streams.
2560 x 1440 resolution at 24 bits per pixel = 88,473,600 bits
At 60Hz, that's 5,308,416,000 bits per second. So a little more than half the claimed 10Gbit bandwidth of Thunderbolt. I guess you're not going to be running two of them on the same port.
If I was editing movies it'd be a different story.