We received Thunderbolt, on the PC at least, a year ago. While not yet ubiquitous, we will be receiving an update to the interface sooner than you would expect. The main advantages of Thunderbolt is the ridiculous bandwidth and ability to daisy-chain with displays. Thunderbolt 2 looks to advance both of those features.
Thunderbolt is based around a PCI Express signal for data and DisplayPort for video, both combined down a single cable. The cable, in fact, is compatible with Mini DisplayPort adapters and devices if used exclusively for video. The upgrade to Thunderbolt 2 advances the video standard to DisplayPort 1.2; as a result, Thunderbolt 2 devices will be capable of driving a 4K monitor (supposedly with sound) without requiring multiple cables to be connected.
In terms of strict bandwidth, Thunderbolt 2 will provide double the data rate of the original Thunderbolt. Instead of 10Gbps, new devices will be able to transfer at 20Gbps. This is especially useful for video content creators looking to manage, in real time, 4K or 120Hz data transferring between cameras and video gear. Struggling with large video capture bandwidth is something we know about…
As expected, there is not really any talk about specific prices yet (I would expect that depends on implementation) but you should look forward to it landing either really late this year or early next year. As for the original Thunderbolt? Well, the new standard is backwards compatible but there is concern whether new devices would be fairly crippled without the new standard.