Talking up Interop 2007, Cisco's Chairman and CEO John Chambers showed the power and flexibility of the phrase "Web 2.0" by proclaiming it to be collaboration and video conferencing. Standing behind Chambers was the Cisco TelePresence system that delivers 1080p (1920x1080) video conferencing to anyone who can afford the $80K to $300K solution along with a fat pipe capable of sparing 4-8 mbps of throughput.
The cost justification for such an expensive solution is that it will save a lot of money on travel costs and lost time. However, don't expect to use this unit to interoperate with other video conferencing vendors like LifeSize or Polycom. It's strictly a proprietary solution designed to work with other Cisco TelePresence systems capable of 1080p video conferencing. The upside to Cisco's solution is that it offers unprecedented video quality.
LifeSize and Polycom offers a lower resolution version of HD video conferencing at 720p (1280x720) resolution which are interoperable with each other as well as older standard definition conferencing devices. This is more of a compromise solution that bridges the gap between standard definition and 1080p while offering backward compatibility. Another benefit of HD conferencing is that the sound quality with 44.1 KHz sampling is far superior to any narrowband 8 KHz telephone call. 720p requires 1-2 mbps (depending on amount of movement in the picture) while standard definition video conferencing requires 0.5 to 1 mbps to work properly. When there are only a few talking heads, the lower bit rates work fine but compression artifacts become noticeable when the person on the other end walks or moves around or the camera pans. The higher bitrates look better under a variety of conditions.
[Update 5/25/2007 - Tandberg is also a dominant maker of Video conferencing solutions and they offer a free 720P HD conferencing software upgrade (under maintenance contract) to a large install base of existing customers. The software update allows the reception of 720p but a new $6K HD camera must be purchased to transmit the video.]